common rail

Diesel Injection Pump

COMMON RAIL SYSTEM (CRS)

OPERATION

September, 2007

00400534E

SERVICE MANUAL

Revision History

Revision HistoryDate Revision Contents

2007. 09 • SCV: Explanation of compact SCV added to "Suction Control Valve (SCV)". (Operation: Referto page 1-30.)

• "Repair" section added.

Table of Contents

Table of Contents

Operation Section

1. GENERAL DESCRIPTION1.1 Changes In Environment Surrounding The Diesel Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

1.2 Demands On Fuel Injection System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

1.3 Types Of And Transitions In ECD (ELECTRONICALLY CONTROLLED DIESEL) Systems . . . . . . . . . . . . . . 1-3

1.4 Common Rail System Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

1.5 Common Rail System And Supply Pump Transitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

1.6 Injector Transitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

1.7 Common Rail System Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6

2. COMMON RAIL SYSTEM OUTLINE2.1 Layout of Main Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7

3. SUPPLY PUMP DESCRIPTION3.1 HP0 Type. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12

3.2 HP2 Type. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-18

3.3 HP3 Type. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-27

3.4 HP4 Type. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-41

4. RAIL DESCCRIPTION4.1 Rail Functions and Composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-46

4.2 Component Part Construction and Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-46

5. INJECTOR DESCRIPTION5.1 General Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-50

5.2 Injector Construction and Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-51

5.3 Injector Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-54

5.4 Injector Actuation Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-54

5.5 Other Injector Component Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-56

6. DESCRIPTION OF CONTROL SYSTEM COMPONENTS6.1 Engine Control System Diagram (Reference) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-59

6.2 Engine ECU (Electronic Control Unit) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-60

6.3 EDU (Electronic Driving Unit) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-60

6.4 Various Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-61

7. CONTROL SYSTEM7.1 Fuel Injection Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-66

7.2 E-EGR System (Electric-Exhaust Gas Recirculation) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-76

7.3 Electronically Controlled Throttle (Not Made By DENSO). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-78

7.4 Exhaust Gas Control System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-79

7.5 DPF System (Diesel Particulate Filter) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-80

7.6 DPNR SYSTEM (DIESEL PARTICULATE NOx REDUCTION). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-82

Table of Contents

8. DIAGNOSIS8.1 Outline Of The Diagnostic Function. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-83

8.2 Diagnosis Inspection Using DST-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-83

8.3 Diagnosis Inspection Using The MIL (Malfunction Indicator Light) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-84

8.4 Throttle Body Function Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-86

9. END OF VOLUME MATERIALS9.1 Particulate Matter (PM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-87

9.2 Common Rail Type Fuel Injection System Development History And The World’s Manufacturers. . . . . . . . . 1-87

9.3 Higher Injection Pressure, Optimized Injection Rates, Higher Injection Timing Control Precision, Higher Injection

Quantity Control Precision. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-88

9.4 Image Of Combustion Chamber Interior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-90

Repair Section

1. DIESEL ENGINE MALFUNCTIONS AND DIAGNOSTIC METHODS (BASIC KNOWL-EDGE)1.1 Combustion State and Malfunction Cause . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-91

1.2 Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-92

2. DIAGNOSIS OVERVIEW2.1 Diagnostic Work Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-93

2.2 Inquiries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-94

2.3 Non-Reoccurring Malfunctions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-96

3. DTC READING (FOR TOYOTA VEHICLES)3.1 DST-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-98

3.2 DTC Check (Code Reading via the DST-2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-98

3.3 DTC Memory Erasure (via the DST-2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-98

4. TROUBLESHOOTING BY SYSTEM4.1 Intake System Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-99

4.2 Fuel System Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-99

4.3 Basics of Electrical/Electronic Circuit Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-102

5. TROUBLESHOOTING5.1 Troubleshooting According to Malfunction Symptom (for TOYOTA Vehicles). . . . . . . . . . . . . . . . . . . . . . . . 2-107

5.2 Other Malfunction Symptoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-122

6. DIAGNOSIS CODES (DTC)6.1 DTC Chart (Example) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-124

Operation Section1–1

1. GENERAL DESCRIPTION

1.1 Changes In Environment Surrounding The Diesel EngineThroughout the world, there is a desperate need to improve vehicle fuel economy for the purposes of preventing global

warming and reducing exhaust gas emissions that affect human health. Diesel engine vehicles are highly acclaimed in

Europe, due to the good fuel economy that diesel fuel offers. On the other hand, the "nitrogen oxides (NOx)" and "par-

ticulate matter (PM)" contained in the exhaust gas must be greatly reduced to meet exhaust gas regulations, and tech-

nology is being actively developed for the sake of improved fuel economy and reduced exhaust gases.

(1) Demands on Diesel Vehicles

• Reduce exhaust gases (NOx, PM, carbon monoxide (CO), hydrocarbon (HC) and smoke).

• Improve fuel economy.

• Reduce noise.

• Improve power output and driving performance.

(2) Transition of Exhaust Gas Regulations (Example of Large Vehicle Diesel Regulations)

• The EURO IV regulations take effect in Europe from 2005, and the 2004 MY regulations take effect in North America

from 2004. Furthermore, the EURO V regulations will take effect in Europe from 2008, and the 2007 MY regulations

will take effect in North America from 2007. Through these measures, PM and NOx emissions are being reduced in

stages.

Q000989E

PM

g/kWh

NOx

g/kWh

2005 20082004 2007

3.5

2.0

2.7

0.27

1998 MY 2004 MY 2007 MY

EURO EURO EURO EURO EURO EURO

1998 MY 2004 MY 2007 MY

0.013

0.130.11

0.03

Europe Europe

North America

North

America

2005 20082004 2007


1.2 Demands On Fuel Injection SystemIn order to address the various demands that are imposed on diesel vehicles, the fuel injection system (including the

injection pump and nozzles) plays a significant role because it directly affects the performance of the engine and the

vehicle. Some of the demands are: higher injection pressure, optimized injection rate, higher precision of injection timing

control, and higher precision of injection quantity control.

< NOTE >

For further information on higher injection pressure, optimized injection rate, higher precision of injection timing control,

and higher precision of injection quantity control, see the material at the end of this document.


1.3 Types Of And Transitions In ECD (ELECTRONICALLY CONTROLLEDDIESEL) Systems

ECD systems include the ECD-V series (V3, V4, and V5) which implements electronic control through distributed pumps

(VE type pumps), and common rail systems made up of a supply pump, rail, and injectors. Types are the ECD-V3 and

V5 for passenger cars and RVs, the ECD-V4 that can also support small trucks, common rail systems for trucks, and

common rail systems for passenger cars and RVs. In addition, there are 2nd-generation common rail systems that sup-

port both large vehicle and passenger car applications. The chart below shows the characteristics of these systems.

ECD-V1

ECD-V3

ECD-V4

ECD-V5

'85 '90 '95 '00

Large Vehicle Common Rail(HP0)

(HP2)Passenger Car Common Rail

Common Rail System

· Maximum Injection Pressure 180 MPa

· Uses pilot injection to reduce the engine combustion noise

· Fuel raised to high pressure by the supply pump is temporarily accumulated in the rail, then injected after the injector is energized.

System

Types and

Transitions


· Inner Cam Pumping Mechanism


· Uses pilot injection to reduce the engine combustion noise.

Supply Pump Injector Rail

· The world's first SPV (electromagnetic spill valve system) is used for fuel injection quantity control, so the quantity injected by each cylinder can be controlled.


Q000750E

ECD-V3 ECD-V4 ECD-V5


1.4 Common Rail System CharacteristicsThe common rail system uses a type of accumulation chamber called a rail to store pressurized fuel, and injectors that

contain electronically controlled solenoid valves to inject the pressurized fuel into the cylinders.

Because the engine ECU controls the injection system (including the injection pressure, injection rate, and injection tim-

ing), the injection system is independent and thus unaffected by the engine speed or load.

Because the engine ECU can control injection quantity and timing to a high level of precision, even multi-injection (mul-

tiple fuel injections in one injection stroke) is possible.

This ensures a stable injection pressure at all times, even in the low engine speed range, and dramatically decreases

the amount of black smoke ordinarily emitted by a diesel engine during start-up and acceleration. As a result, exhaust

gas emissions are cleaner and reduced, and higher power output is achieved.

(1) Features of Injection Control

Injection Pressure Control• Enables high-pressure injection even at low engine speeds.

• Optimizes control to minimize particulate matter and NOx emissions.

Injection Timing Control• Enables finely tuned optimized control in accordance with driving conditions.

Injection Rate Control• Pilot injection control injects a small amount of fuel before the main injection.

· Injection pressure is more than double the current pressure, which makes it possible to greatly reduce particulate matter.

Common Rail System

Injection Pressure Control Injection Timing Control Injection Rate Control

Injection Quantity Control

Electronic Control Type

Common Rail System

Conventional

Pump

Optimized and Higher Pressure

Speed

Speed

Injection Quantity

Injection Pressure

Pre-Injection

Pilot injection After-Injection

Post-Injection

Main Injection

1 3 2 4

Inje

ctio

n P

ressu

re

Pa

rtic

ula

te

Inje

ctio

n R

ate

Crankshaft Angle

Cylinder Injection Quantity Correction

Inje

ctio

n Q

uant

ity

Adv

ance

Ang

le

Q000751E


1.5 Common Rail System And Supply Pump TransitionsThe world's first common rail system for trucks was introduced in 1995. In 1999, the common rail system for passenger

cars (the HP2 supply pump) was introduced, and then in 2001 a common rail system using the HP3 pump (a lighter and

more compact supply pump) was introduced. In 2004, the three-cylinder HP4 based on the HP3 was introduced.

1.6 Injector Transitions

Q000752E

1996 1998 2000 2002 2004 2006

120MPa

180MPa

135MPa

HP0

HP2HP3

Large Trucks

Medium-Size Trucks

Common Rail

System1st Generation Common Rail System 2nd Generation Common Rail System

Passenger Vehicles

Compact Trucks

Suction Quantity Adjustment



Pre-Stroke Quantity Adjustment180MPa

HP4

Q000753E

· 180MPa

· 135MPa

· 120MPa

X1 G2

97 98 99 00 01 02 03

1st Generation 2nd Generation

· Multi-Injection

· Pilot Injection

· Pilot Injection

X2


1.7 Common Rail System ConfigurationThe common rail control system can be broadly divided into the following four areas: sensors, engine ECU, EDU, and

actuators.

SensorsDetect the condition of the engine and the pump.

Engine ECUReceives signals from the sensors, calculates the proper injection quantity and injection timing for optimal engine oper-

ation, and sends the appropriate signals to the actuators.

EDUEnables the injectors to be actuated at high speeds. There are also types with charge circuits within the ECU that serve

the same role as the EDU. In this case, there is no EDU.

ActuatorsOperate to provide optimal injection quantity and injection timing in accordance with the signals received from the en-

gine ECU.

Engine Speed Sensor /

TDC (G) Sensor

Accelerator Position Sensor

Other Sensors and Switches

Engine ECU

EDU

Supply Pump (SCV: Suction Control Valve)

Injector

Other Actuators

DiagnosisQ000754E


2. COMMON RAIL SYSTEM OUTLINE

2.1 Layout of Main ComponentsCommon rail systems are mainly made up of the supply pump, rail, and injectors. There are the following types accord-

ing to the supply pump used.

(1) HP0 Type

• This system is the first common rail system that DENSO commercialized. It uses an HP0 type supply pump and is

mounted in large trucks and large buses.

Exterior View of Main System Components

Configuration of Main System Components (Example of HP0)

Q000755E

InjectorSupply Pump (HP0 Type)

Rail

Q000756E

Supply Pump

PCV (Pump Control Valve)

Cylinder

Recognition Sensor

(TDC (G) Sensor)

Rail Pressure Sensor

Rail

Engine ECU

Injector

Accelerator

Position Sensor

Crankshaft Position Sensor (Engine Speed Sensor)

Fuel Temperature Sensor

Coolant Temperature

Sensor


(2) HP2 Type

• This system uses a type of HP2 supply pump that has been made lighter and more compact, and is the common rail

system for passenger cars and RVs instead of the ECD-V3.


Mounting Diagram of Main System Components

Q000757E

InjectorSupply Pump (HP2 Type)

Rail

Engine ECU

EDU (Electronic Driving Unit)

EGR Valve

E-VRV

Intake Air Temperature

Sensor

Intake Air Pressure Sensor

Injector

Crankshaft Position Sensor

(Engine Speed Sensor) RailSupply Pump Cylinder Recognition Sensor

(TDC (G) Sensor)



Coolant Temperature

Sensor

Q000758E


Overall System Flow (Fuel)

Q000926E

Supply Pump

PlungerFeed Pump

Delivery Valve

SCV (Suction Control Valve)

Inner Cam

Regulating Valve

Check Valve

RailRail Pressure Sensor

Pressure Limiter

Injector

TWV

Engine

ECUEDUVarious Sensors

Fuel Filter

Fuel Tank

: Flow of Injection Fuel

: Flow of Leak Fuel


(3) HP3 Type, HP4 Type

HP3 Type• This system uses an HP3 type supply pump that is compact, lightweight and provides higher pressure. It is mostly

mounted in passenger cars and small trucks.

HP4 Type• This system is basically the same as the HP3 type, however it uses the HP4 type supply pump, which has an in-

creased pumping quantity to handle larger engines. This system is mostly mounted in medium-size trucks.


Mounting Diagram for Main System Components

Q000759E

HP3 HP4

InjectorSupply Pump

Rail

Q000760E

Supply Pump

SCV (Suction Control

Valve)



Injector

Engine ECU

EDU

DLC3 Connector

R/B

EGR Valve E-VRV for EGR

EGR Shut-Off VSV

Throttle Body


Cylinder Recognition Sensor (TDC (G) Sensor)



Airflow Meter (with Intake Air

Temperature Sensor)

Coolant Temperature Sensor

HP3 HP4

(Suction Control Valve)

SCV

Pressure Discharge Valve



Overall System Flow (Fuel)

Q000927E

Supply Pump

(HP3 or HP4)

Plunger

Feed Pump

Delivery

Valve

SCV (Suction

Control Valve)

Rail



Pressure Limiter

Injector

ECU

EDU

Various Sensors

Fuel Filter

Fuel Tank

: Flow of Injection Fuel

: Flow of Leak Fuel


3. SUPPLY PUMP DESCRIPTION

3.1 HP0 Type

(1) Construction and Characteristics

• The HP0 supply pump is mainly made up of a pumping system as in conventional in-line pumps (two cylinders), the

PCV (Pump Control Valve) for controlling the fuel discharge quantity, the cylinder recognition sensor TDC (G) sen-

sor, and the feed pump.

• It supports the number of engine cylinders by changing the number of peaks on the cam. The supply pump rotates at

half the speed of the engine. The relationship between the number of engine cylinders and the supply pump pumping

is as shown in the table below.

• By increasing the number of cam peaks to handle the number of engine cylinders, a compact, two-cylinder pump unit

is achieved. Furthermore, because this pump has the same number of pumping strokes as injections, it maintains a

smooth and stable rail pressure.

Number of Engine CylindersSpeed Ratio

(Pump: Engine)

Supply PumpNumber of Pumping Rotations for 1

Cycle of the Engine (2 Rotations)Number of

CylindersCam Peaks

4 Cylinders

1 : 2 2

2 4

6 Cylinders 3 6

8 Cylinders 4 8

Feed Pump

Delivery Valve

Cam x 2


Tappet

Element

Cylinder Recognition Sensor

(TDC (G) Sensor)

Pulsar for TDC (G) Sensor

Overflow Valve

Q000768E


(2) Exploded View

Q000769E

PCV

(Pump Control Valve)

Delivery ValveElement


(TDC (G) Sensor)

RollerCam

Camshaft

Tappet

Feed Pump

Priming Pump


(3) Supply Pump Component Part Functions

Feed Pump• The feed pump, which is integrated in the supply pump, draws fuel from the fuel tank and feeds it to the pump chamber

via the fuel filter. There are two types of feed pumps, the trochoid type and the vane type.

Trochoid Type- The camshaft actuates the outer/inner rotors of the feed pump, causing them to start rotating. In accordance with

the space produced by the movement of the outer/inner rotors, the feed pump draws fuel into the suction port and

pumps fuel out the discharge port.

Vane Type- The camshaft actuates the feed pump rotor and the vanes slide along the inner circumference of the eccentric ring.

Along with the rotation of the rotor, the pump draws fuel from the fuel tank, and discharges it to the SCV and the

pumping mechanism.

Component Parts Functions

Feed Pump Draws fuel from the fuel tank and feeds it to the pumping mechanism.

Overflow Valve Regulates the pressure of the fuel in the supply pump.

PCV (Pump Control Valve) Controls the quantity of fuel delivered to the rail.

Pumping Mechanism

Cam Actuates the tappet.

Tappet Transmits reciprocating motion to the plunger.

Plunger Moves reciprocally to draw and compress fuel.

Delivery Valve Stops the reverse flow of fuel pumped to the rail.

Cylinder Recognition Sensor TDC (G)Sensor

Identifies the engine cylinders.

To Pump Chamber

From Fuel Tank

Outer Rotor

Inner Rotor

Suction Port Discharge Port

Q000770E

Suction Port

Discharge Port

Rotor Eccentric Ring

Vane

Q000771E


PCV: Pump Control Valve• The PCV (Pump Control Valve) regulates the fuel discharge quantity from the supply pump in order to regulate the

rail pressure. The fuel quantity discharged from the supply pump to the rail is determined by the timing with which the

current is applied to the PCV.

Actuation Circuit- The diagram below shows the actuation circuit of the PCV. The ignition switch turns the PCV relay ON and OFF to

apply current to the PCV. The ECU handles ON/OFF control of the PCV. Based on the signals from each sensor,

it determines the target discharge quantity required to provide optimum rail pressure and controls the ON/OFF tim-

ing for the PCV to achieve this target discharge quantity.

Pumping Mechanism• The camshaft is actuated by the engine and the cam actuates the plunger via the tappet to pump the fuel sent by the

feed pump. The PCV controls the discharge quantity. The fuel is pumped from the feed pump to the cylinder, and then

to the delivery valve.

PCV

Ignition Switch

+B

PCV Relay

PCV1

PCV2

From PCV relay

To Rail

Q000772E

Q000773E

Camshaft

Feed Pump


Pulsar for TDC (G) Sensor

Delivery Valve

Cam (3 Lobes: 6-Cylinders)

Plunger

To Rail


CYLINDER RECOGNITION SENSOR TDC (G) SENSOR• The cylinder recognition sensor TDC (G) sensor uses the alternating current voltage generated by the change in the

lines of magnetic force passing through the coil to send the output voltage to the ECU. This is the same for the engine

speed sensor installed on the engine side. A disc-shaped gear, which is provided in the center of the supply pump

camshaft, has cutouts that are placed at 120? intervals, plus an extra cutout. Therefore, this gear outputs seven puls-

es for every two revolutions of the engine (for a six-cylinder engine). Through the combination of engine-side engine

speed pulses and TDC pulses, the pulse after the extra cutout pulse is recognized as the No. 1 cylinder.

Q000774E

0 2 4 6 8 101214 0 2 4 6 810 12 14 0 2 4 6 8 10 12 0 2 4 6 8 101214 0 2 4 6 8 101214 0 2 4 6 8 0 2 4 6 81012


(TDC (G) Sensor)

No.6 Cylinder TDC (G) Standard Pulse No.1 Cylinder Recognition TDC (G) Pulse

No.1 Cylinder TDC (G) Pulse

No.1 Cylinder Engine Speed Standard Pulse No.6 Cylinder Engine Speed Standard Pulse

· TDC (G) Pulse

· Engine Speed Pulse

· For a 6-Cylinder Engine (Reference)


(4) Supply Pump Operation

Supply Pump Overall Fuel Flow• The fuel is drawn by the feed pump from the fuel tank and sent to the pumping mechanism via the PCV. The PCV

adjusts the quantity of fuel pumped by the pumping mechanism to the necessary discharge quantity, and the fuel is

pumped to the rail via the delivery valve.

Fuel Discharge Quantity Control• The fuel sent from the feed pump is pumped by the plunger. In order to adjust the rail pressure, the PCV controls the

discharge quantity. Actual operation is as follows.

PCV and Plunger Operation During Each Stroke

Intake Stroke (A) In the plunger's descent stroke, the PCV opens and low-pressure fuel is suctioned into theplunger chamber via the PCV.

Pre-Stroke (B) Even when the plunger enters its ascent stroke, the PCV remains open while it is not energized.During this time, fuel drawn in through the PCV is returned through the PCV without being pres-surized (pre-stroke).

Pumping Stroke (C) At a timing suited to the required discharge quantity, power is supplied to close the PCV, thereturn passage closes, and pressure in the plunger chamber rises. Therefore, the fuel passesthrough the delivery valve (reverse cut-off valve) and is pumped to the rail. Specifically, theplunger lift portion after the PCV closes becomes the discharge quantity, and by varying the tim-ing for the PCV closing (the end point of the plunger pre-stroke), the discharge quantity is variedto control the rail pressure.

Intake Stroke (A) When the cam exceeds the maximum lift, the plunger enters its descent stroke and pressure inthe plunger chamber decreases. At this time, the delivery valve closes and fuel pumping stops. Inaddition, the PCV opens because it is de-energized, and low-pressure fuel is suctioned into theplunger chamber. Specifically, the system goes into state A.

Q000775E

Cam Lift

PCV Operation Close Valve

Intake Stroke Pumping Stroke

Pre-Stroke

Open Valve

PCV

Pump Operation

Plunger

Return

When Discharge Quantity Increases

When Discharge Quantity Decreases

To Rail

Pumping the Required

Discharge Quantity

H

Discharge Quantity

h

Q=4

2d (H-h)

(A) (B) (C) (A')

Delivery Valve

From Fuel Tank

Pumping

Mechanism

d


3.2 HP2 Type


• The supply pump is primarily composed of the two pumping mechanism (inner cam, roller, two plungers) systems,

the SCV (Suction Control Valve), the fuel temperature sensor, and the feed pump (vane type), and is actuated with

half the engine rotation.

• The pumping mechanism consists of an inner cam and a plunger, and forms a tandem configuration in which two sys-

tems are arranged axially. This makes the supply pump compact and reduces the peak torque.

• The quantity of fuel discharged to the rail is controlled by the fuel suction quantity using SCV (Suction Control Valve)

control. In order to control the discharge quantity with the suction quantity, excess pumping operations are eliminated,

reducing the actuation load and suppressing the rise in fuel temperature.

Regulating Valve

Plunger

Feed Pump

Inner Cam

Roller


Delivery Valve


Check Valve

Overflow

Fuel Suction (From Fuel Tank)

Q000818E


(2) Supply Pump Actuating Torque

• Because the pumping mechanism is a tandem configuration, its peak actuating torque is one-half that of a single

pump with the same discharge capacity.

Pumping

Pumping

PumpingSuction

Pumping

Feed

Feed

Plunger 2 Plunger 1

Tor

que

(Oil

Pum

ping

Rat

e)

Tor

que

(Oil

Pum

ping

Rat

e)

Co

mp

ositio

n

Single Type Tandem Type

To

rqu

e P

att

ern

Solid Line : Plunger 1Broken Line: Plunger 2

Q000819E


(3) Exploded View

Pump Body

Feed Pump

Camshaft

Inner Cam

Roller

Shoe

Delivery Valve


Check Valve


Regulating Valve

Q000820E


(4) Component Part Functions

Feed Pump• The feed pump is a four-vaned type that draws fuel from the fuel tank and discharges it to the pumping mechanism.

The rotation of the drive shaft causes the feed pump rotor to rotate and the vane to move by sliding along the inner

surface of the casing (eccentric ring). Along with the rotation of the rotor, the pump draws fuel from the fuel tank, and

discharges it to the SCV and the pumping mechanism. To keep the vane pressed against the inner circumference, a

spring is provided inside each vane, in order to minimize fuel leakage within the pump.

Regulating Valve• The purpose of the regulating valve is to control the feed pressure (fuel pumping pressure) sending fuel to the pump-

ing mechanism. As the rotational movement of the pump increases and the feed pressure exceeds the pressure set

at the regulating valve, the valve opens by overcoming the spring force, allowing the fuel to return to the suction side.


Feed Pump Draws fuel from the fuel tank and feeds it to the pumping mechanism.

Regulating Valve Regulates internal fuel pressure in the supply pump.

SCV (Suction Control Valve) Controls the quantity of fuel that is fed to the plunger in order to control fuelpressure in the rail.

Pumping Mechanism

Inner Cam Actuates the plunger.

Roller Actuates the plunger.


Delivery Valve Maintains high pressure by separating the pressurized area (rail) from thepumping mechanism.

Fuel Temperature Sensor Detects the fuel temperature.

Check Valve Prevents the pressurized fuel in the pumping mechanism from flowing backinto the suction side.

Q000821E

Rotor

Eccentric Ring

Spring

Vane

Front Cover Rear Cover

Regulating Valve

Open Valve Pressure Characteristic

Open Valve Pressure High

Open Valve Pressure Low

Speed

Fe

ed

Pre

ssu

re (

Pu

mp

ing

Pre

ssu

re)

Regulating Valve

Feed Pump

(Discharge Side)

Suction Inlet

Filter

Feed Pump

(Suction Side)

Regulating Valve Body

Spring

Piston

BushingQ000822E


SCV: Suction Control Valve • A solenoid type valve has been adopted. The ECU controls the duration of the current applied to the SCV in order to

control the quantity of fuel drawn into the pumping mechanism. Because only the quantity of fuel required to achieve

the target rail pressure is drawn in, the actuating load of the supply pump decreases, thus improving fuel economy.

SCV ON- When current is applied to the coil, it pulls the needle valve upward, allowing fuel to be drawn into the pumping

mechanism of the supply pump.

SCV OFF- When current is no longer applied to the coil, the needle valve closes and stops the suction of fuel.

Needle Valve

Spring

Stopper Coil

Q000823E

To Pump Pumping Mechanism

From Feed Pump Q000824E

From Feed PumpQ000825E


Pumping Mechanism (Plunger, Inner Cam, Roller)• The pumping mechanism is made up of the plunger, inner cam, and roller, and it draws in the fuel discharged by the

feed pump and pumps it to the rail. Because the drive shaft and the inner cam have an integral construction, the ro-

tation of the drive shaft directly becomes the rotation of the inner cam.

• Two plunger systems are arranged in series (tandem type) inside the inner cam. Plunger 1 is situated horizontally,

and plunger 2 is situated vertically. Plunger 1 and plunger 2 have their suction and compression strokes reversed

(when one is on the intake, the other is discharging), and each plunger discharges twice for each one rotation, so for

one rotation of the supply pump, they discharge a total of four times to the rail.

Delivery Valve• The delivery valve, which contains two valve balls, delivers the pressurized fuel from plungers 1 and 2 to the rail in

alternating strokes. When the pressure in the plunger exceeds the pressure in the rail, the valve opens to discharge

fuel.

Inner Cam (Cam Lift: 3.4mm)

RollerRoller Diameter: 9Roller Length: 21mmMaterial: Reinforced Ceramic

Plunger 1 (Horizontal)

Plunger 2 (Vertical)

· Plunger 1: Medium + Medium· Plunger 2: Short + Long

Plunger Length Combination

Cam 90 Rotation

Plunger 1: Start of PumpingPlunger 2: Start of Suction

Plunger 1: Start of SuctionPlunger 2: Start of Pumping

Plunger 1

Plunger 2

Q000826E

From Plunger 1

From Plunger 2

Pin

Gasket

Guide

Valve Ball

Stopper Holder

To Rail

· When Plunger 1 Pumping · When Plunger 2 Pumping

Q000827E


Fuel Temperature Sensor• The fuel temperature sensor is installed on the fuel intake side and utilizes the characteristics of a thermistor in which

the electric resistance changes with the temperature in order to detect the fuel temperature.

Check Valve• The check valve, which is located between the SCV (Suction Control Valve) and the pumping mechanism, prevents

the pressurized fuel in the pumping mechanism from flowing back into the SCV.

Check Valve Open- During fuel suction (SCV ON), the feed pressure opens the valve, allowing fuel to be drawn into the pumping mech-

anism.

Check Valve Closed- During fuel pumping (SCV OFF), the pressurized fuel in the pumping mechanism closes the valve, preventing fuel

from flowing back into the SCV.

Resistance - Temperature Characteristic

Temperature Resis

tance V

alu

e

Thermistor

Q000828E

Pump Housing Spring Valve

Stopper PlugTo SCV

To Pumping Mechanism

Q000829E

From SCV

To Pumping Mechanism

Q000830E

From Pumping Mechanism

Q000831E



Supply Pump Overall Fuel Flow• Fuel is suctioned by the feed pump from the fuel tank and sent to the SCV. At this time, the regulating valve adjusts

the fuel pressure to below a certain level. Fuel sent to the feed pump has the required discharge quantity adjusted by

the SCV and enters the pumping mechanism through the check valve. The fuel pumped by the pumping mechanism

is pumped through the delivery valve to the rail.

From Fuel Tank

Feed Pump

Plunger

Cam

Head

SCV2

Check Valve 1

Check Valve 2

SCV1

To Rail

Delivery ValveTo Tank

Overflow Orifice

Regulating Valve

Q000832E


Fuel Discharge Quantity Control• The diagram below shows that the suction starting timing (SCV (Suction Control Valve) ON) is constant (determined

by the pump speed) due to the crankshaft position sensor signal. For this reason, the fuel suction quantity is controlled

by changing the suction ending timing (SCV OFF). Hence, the suction quantity decreases when the SCV is turned

OFF early and the quantity increases when the SCV is turned OFF late.

• During the intake stroke, the plunger receives the fuel feed pressure and descends along the cam surface. When the

SCV turns OFF (suction end), the feed pressure on the plunger ends and the descent stops. Since the suction quantity

varies, when suction ends (except for maximum suction) the roller separates from the cam surface.

• When the drive shaft rotates and the cam peak rises and the roller comes in contact with the cam surface again, the

plunger is pressed by the cam and starts pumping. Since the suction quantity = the discharge quantity, the discharge

quantity is controlled by the timing with which the SCV is switched OFF (suction quantity).

0 2 4 6 8 10121416 0 2 4 6 8 101214 0 2 4 6 8 10121416 0 2 4 6 8 101214

Suction Suction

Suction SuctionDecreased Suction Quantity

Increased Suction Quantity

ON

OFFSCV 1

SCV 2

Suction Pumping

Start of Suction End of Suction Start of Pumping End of Pumping

360 CR

TDC #1 TDC #3 TDC #4 TDC #2

Cylinder Recognition Sensor Signal

Crankshaft Position Sensor Signal

ON

OFF

Crankshaft Angle

Compression Top Dead Center

Fuel

ON

Plunger

Roller

OFF

Fuel

OFF

Fuel

OFF

Delivery Valve

Discharge

Horizontal

Cam Lift

Vertical

Cam Lift

Check Valve

SCV

Pumping Suction

Pumping SuctionPumping Suction

Pumping Suction

Delivery Valve

Q000833E


3.3 HP3 Type


• The supply pump is primarily composed of the pump unit (eccentric cam, ring cam, two plungers), the SCV (suction

control valve), the fuel temperature sensor and the feed pump (trochoid type), and is actuated at 1/1 or 1/2 the engine

rotation.

• The two compact pump unit plungers are positioned symmetrically above and below on the outside of the ring cam.

• The fuel discharge quantity is controlled by the SCV, the same as for the HP2, in order to reduce the actuating load

and suppress the rise in fuel temperature. In addition, there are two types of HP3 SCV: the normally open type (the

suction valve opens when not energized) and the normally closed type (the suction valve is closed when not ener-

gized).

• With a DPNR system (Diesel Particulate NOx Reduction) system, there is also a flow damper. The purpose of this

flow damper is to automatically shut off the fuel if a leak occurs in the fuel addition valve passage within the DPNR.

Q000835E

Suction Valve

Plunger

Ring Cam SCV (Suction Control Valve)

Delivery Valve

Feed Pump



(2) Exploded View

Q000836E

Pump Housing

Camshaft

Eccentric Cam

Ring Cam

Feed Pump

Plunger

Element Sub-Assembly


Regulating Valve


Delivery Valve

Delivery Valve

Delivery Valve

Element Sub-Assembly

Plunger



Feed Pump• The trochoid type feed pump, which is integrated in the supply pump, draws fuel from the fuel tank and feeds it to the

two plungers via the fuel filter and the SCV (Suction Control Valve). The drive shaft actuates the outer/inner rotors of

the feed pump, thus causing the rotors to start rotating. In accordance with the space that increases and decreases

with the movement of the outer and inner rotors, the feed pump draws fuel into the suction port and pumps fuel out

the discharge port.

Regulating Valve• The regulating valve keeps the fuel feed pressure (discharge pressure) below a certain level. If the pump speed in-

creases and the feed pressure exceeds the preset pressure of the regulating valve, the valve opens by overcoming

the spring force in order to return the fuel to the suction side.


Feed Pump Draws fuel from the fuel tank and feeds it to the plunger.

Regulating Valve Regulates the pressure of the fuel in the supply pump.

SCV (Suction Control Valve) Controls the quantity of fuel that is fed to the plungers.

Pump Unit Eccentric Cam Actuates the ring cam.

Ring Cam Actuates the plunger.


Delivery Valve Prevents reverse flow from the rail of the fuel pumped from the plunger.


To Pump Chamber

From Fuel Tank

Outer Rotor

Inner Rotor

Suction Port Discharge Port

Q000770E

Bushing

Piston

Spring

Plug

Feed Pump

SCV

Pump Housing

Q000837E


Suction Control Valve (SCV)• In contrast to the HP2, the SCV for the HP3 supply pump is equipped with a linear solenoid valve. The fuel flow vol-

ume supplied to the high-pressure plunger is controlled by adjusting the engine ECU supplies power to the SCV (duty

ratio control). When current flows to the SCV, the internal armature moves according to the duty ratio. The armature

moves the needle valve, controlling the fuel flow volume according to the amount that the valve body fuel path is

blocked. Control is performed so that the supply pump suctions only the necessary fuel quantity to achieve the target

rail pressure. As a result, the supply pump actuation load is reduced.

• There are two types of HP3 SCV: the normally open type (the suction valve opens when not energized) and the nor-

mally closed type (the suction valve is closed when not energized). The operation of each type is the reverse of that

of the other.

• In recent years, a compact SCV has been developed. Compared to the conventional SCV, the position of the return

spring and needle valve in the compact SCV are reversed. For this reason, operation is also reversed.

Normally Open Type- When the solenoid is not energized, the return spring pushes against the needle valve, completely opening the fuel

passage and supplying fuel to the plungers. (Total quantity suctioned → Total quantity discharged)

- When the solenoid is energized, the armature pushes the needle valve, which compresses the return spring and

closes the fuel passage. In contrast, the needle valve in the compact SCV is pulled upon, which compresses the

return spring and closes the fuel passage.

- The solenoid ON/OFF is actuated by duty ratio control. Fuel is supplied in an amount corresponding to the open

surface area of the passage, which depends on the duty ratio, and then is discharged by the plungers.

Q002340E

Conventional SCV

External View

Return Spring Solenoid

Valve Body

Cross SectionNeedle Valve

Q002309E

Return Spring

Solenoid

Valve Body

Needle Valve

Compact SCV

External View Cross Section


Duty Ratio Control- The engine ECU outputs sawtooth wave signals with a constant frequency. The value of the current is the effective

(average) value of these signals. As the effective value increases, the valve opening decreases, and as the effec-

tive value decreases, the valve opening increases.

When the SCV Energized Duration (Duty ON Time) is Short- When the SCV energization time is short, the average current flowing through the solenoid is small. As a result, the

needle valve is returned by spring force, creating a large valve opening. Subsequently, the fuel suction quantity

increases.

QD0710E

Average Current Difference

Act

uatin

g V

olta

ge

ON

OFF

Cu

rre

nt

Low Suction Quantity High Suction Quantity

Q002341E

NeedleValve

Large ValveOpening

SCVFeed Pump

Conventional SCV


When the SCV Energized Duration (Duty ON Time) is Long- When the energization time is long, the average current flowing to the solenoid is large. As a result, the needle

valve is pressed out (in the compact SCV, the needle valve is pulled), creating a small valve opening. Subsequently,

the fuel suction quantity decreases.

Q002321E

Compact SCV

Needle ValveLargeOpening

Feed Pump

Q002342E

NeedleValve

Small Opening

SCVFeed Pump

Conventional SCV


Q002322E

Small ValveOpening

Compact SCV

Needle Valve

SCVFeed Pump


Normally Closed Type- When the solenoid is energized, the needle valve is pressed upon (in the compact SCV, the cylinder is pulled upon)

by the armature, completely opening the fuel passage and supplying fuel to the plunger. (Total quantity suctioned

→ Total quantity discharged)

- When power is removed from the solenoid, the return spring presses the needle valve back to the original position,

closing the fuel passage.

- The solenoid ON/OFF is actuated by duty ratio control. Fuel is supplied in an amount corresponding to the open

surface area of the passage, which depends on the duty ratio, and then is discharged by the plungers.

Duty Ratio Control- The engine ECU outputs sawtooth wave signals with a constant frequency. The value of the current is the effective

(average) value of these signals. As the effective value increases, the valve opening increases, and as the effective

value decreases, the valve opening decreases.

Q002343ECross SectionExternal View

Return SpringSolenoid

Valve BodyNeedle Valve

Conventional SCV

Q002323ECross SectionExternal View

Return Spring

SolenoidValve Body

Needle Valve

Compact SCV

Q000844E

Average Current Difference

Actu

atin

g V

olta

ge

ON

OFF

Cu

rre

nt

High Suction Quantity Low Suction Quantity


When the SCV Energized Duration (Duty ON Time) is Long- When the energization time is long, the average current flowing to the solenoid is large. As a result, the needle

valve is pushed out (in the compact SCV, the needle valve is pulled), creating a large valve opening. Subsequently,

the fuel suction quantity increases.

Q002344E

NeedleValve

LargeOpening

SCVFeed PumpConventional SCV

Q002324 E

Large ValveOpening

Compact SCV

NeedleValve

SCVFeed Pump


When the SCV Energized Duration (Duty ON Time) is Short- When the energization time is short, the average current flowing through the solenoid is small. As a result, the nee-

dle valve is returned to the original position by spring force, creating a small valve opening. Subsequently, the fuel

suction quantity decreases.

Q002345E

SCVFeed Pump

SmallOpening

NeedleValve

Conventional SCV

Q002325E

NeedleValve

Small ValveOpening

Compact SCVSCV

Feed Pump


Pump Unit (Eccentric Cam, Ring Cam, Plunger)• The eccentric cam is attached to the camshaft and the ring cam is installed on the eccentric cam. There are two plung-

ers at positions symmetrical above and below the ring cam.

• Because the rotation of the camshaft makes the eccentric cam rotate eccentrically, the ring cam follows this and

moves up and down, and this moves the two plungers reciprocally. (The ring cam itself does not rotate.)

Plunger ARing Cam

Feed Pump

Plunger B

Camshaft

Eccentric CamQ000845E

Q000846E

Ring Cam

Eccentric Cam

Camshaft


Delivery Valve• The delivery valve for the HP3 has an integrated element and is made up of the check ball, spring, and holder. When

the pressure at the plunger exceeds the pressure in the rail, the check ball opens to discharge the fuel.

Fuel Temperature Sensor• The fuel temperature sensor is installed on the fuel intake side and utilizes the characteristics of a thermistor in which

the electric resistance changes with the temperature in order to detect the fuel temperature.

ElementCheck Ball

Spring Holder

Plunger

Q000847E


Temperature

Re

sis

tan

ce

Va

lue

Thermistor

Q000848E



Supply Pump Overall Fuel Flow• The fuel is suctioned by the feed pump from the fuel tank and sent to the SCV. At this time, the regulating valve adjusts

the fuel pressure to below a certain level. The fuel sent from the feed pump has the required discharge quantity ad-

justed by the SCV, and enters the pump unit through the suction valve. The fuel pumped by the pump unit is pumped

through the delivery valve to the rail.

Filter

From Pump

To Rail

Q000849E

Inject Rail

Discharge Valve Suction Valve

Plunger

Return Spring

Return

Combustion Overflow

Camshaft

Fuel Tank

Fuel Filter

(With Priming Pump)

Suction

Fuel Intake Port

Feed Pump

Regulating Valve

Suction Pressure

Feed Pressure

High Pressure

Return Pressure


Operation• The discharge quantity is controlled by SCV control, the same as for the HP2, however it differs from the HP2 in that

the valve opening is adjusted by duty ratio control.

• In the intake stroke, the spring makes the plunger follow the movement of the ring cam, so the plunger descends to-

gether with the ring cam. Thus, unlike the HP2, the plunger itself also suctions in fuel. When the suctioned fuel passes

through the SCV, the flow quantity is controlled to the required discharge quantity by the valve opening and enters

the pump main unit.

• The quantity of fuel adjusted by the SCV is pumped during the pumping stroke.

SCV

Plunger B

Plunger AEccentric Cam

Delivery ValveSuction Valve

Ring Cam

Plunger A: End of Compression

Plunger B: End of Suction

Plunger A: End of Suction

Plunger B: End of Compression

Plunger B: Start of Compression

Plunger A: Start of Suction

Plunger B: Start of Suction

Plunger A: Start of Compression

QD0707E


3.4 HP4 Type


• The HP4 basic supply pump construction is the same as for the HP3. The composition is also the same as the HP3,

being made up of the pump unit (eccentric cam, ring cam, plunger), the SCV (suction control valve), the fuel temper-

ature sensor, and the feed pump. The main difference is that there are three plungers.

• Because there are three plungers, they are positioned at intervals of 120? around the outside of the ring cam. In ad-

dition, the fuel delivery capacity is 1.5 times that of the HP3.

• The fuel discharge quantity is controlled by the SCV, the same as for the HP3.

Q000850E

Suction Valve

Plunger

Eccentric Cam


Delivery Valve

Feed Pump



(2) Exploded View

Q000457E

SCV


Filter

Feed Pump

Regulating Valve

Pump Body

Ring Cam

Camshaft

IN

OUT



• The HP4 supply pump component parts and functions are basically the same as for the HP3. The explanations below

only cover those points on which the HP4 differs from the HP3. For other parts, see the appropriate item in the expla-

nation of the HP3.

Pump Unit (Eccentric Cam, Ring Cam, Plunger)• A triangular ring cam is installed on the eccentric cam on the drive shaft, and three plungers are installed to the ring

cam at intervals of 120°.


Feed Pump Draws fuel from the fuel tank and feeds it to the plunger.

Regulating Valve Regulates the pressure of the fuel in the supply pump.

SCV (Suction Control Valve) Controls the quantity of fuel that is fed to the plungers.

Pump Unit

Eccentric Cam Actuates the ring cam.

Ring Cam Actuates the plunger.


Suction Valve Prevents reverse flow of compressed fuel into the SCV.

Delivery Valve Prevents reverse flow from the rail of the fuel pumped from the plunger.


Ring Cam

Plunger

Camshaft

Eccentric Cam

Q000851E


• Because the rotation of the camshaft makes the eccentric cam rotate eccentrically, the ring cam follows this and this

moves the three plungers reciprocally. (The ring cam itself does not rotate.)

Plunger #1

Plunger #2

Eccentric CamCamshaft

Camshaft

Rotate 120 Clockwise

Camshaft


Camshaft


Ring Cam

Plunger #3

End of Pumping

End of Pumping

End of Pumping

Pumping

Pumping

Pumping

Suction

SuctionSuction

D000852E



Supply Pump Overall Fuel Flow• The fuel is suctioned by the feed pump from the fuel tank and sent to the SCV. At this time, the regulating valve adjusts

the fuel pressure to below a certain level. The fuel sent from the feed pump has the required discharge quantity ad-

justed by the SCV, and enters the pump unit through the suction valve. The fuel pumped by the pump unit is pumped

through the delivery valve to the rail.

Operation• The discharge quantity is controlled by the SCV. As with the HP3, the valve opening is adjusted by duty ratio control.

The only difference from the HP3 is the shape of the pump unit. Operation and control are basically the same. For

details on operation and control, see the explanation of the HP3.

Q000853E

Feed Pump from Fuel Tank (Suction)

SCV from Feed Pump (Low Pressure)

Pump Unit from SCV (Low-Pressure Adjustment Complete)

From Pump Unit to Rail (High Pressure)

From Fuel

Tank

To Rail

Plunger

Suction ValveDelivery Valve

Ring Cam

CamshaftSCV

Feed Pump


4. RAIL DESCCRIPTION

4.1 Rail Functions and CompositionThe function of the rail is to distribute fuel pressurized by the supply pump to each cylinder injector.

The shape of the rail depends on the model and the component parts vary accordingly.

The component parts are the rail pressure sensor (Pc sensor), pressure limiter, and for some models a flow damper and

pressure discharge valve.

4.2 Component Part Construction and Operation


Rail Stores pressurized fuel that has been pumped from the supply pump and distrib-utes the fuel to each cylinder injector.

Pressure Limiter Opens the valve to release pressure if the pressure in the rail becomes abnormallyhigh.

Rail Pressure Sensor (Pc Sensor) Detects the fuel pressure in the rail.

Flow Damper Reduces the pressure pulsations of fuel in the rail. If fuel flows out excessively, thedamper closes the fuel passage to prevent further flow of fuel. Mostly used withengines for large vehicles.

Pressure Discharge Valve Controls the fuel pressure in the rail. Mostly used with engines for passenger cars.

Rail

Rail

Pressure Limiter

Pressure Limiter

Rail Pressure Sensor (Pc Sensor)

Rail Pressure Sensor (Pc Sensor)

Flow Damper


Q000854E


(1) Pressure Limiter

• The pressure limiter opens to release the pressure if abnormally high pressure is generated. If pressure within the rail

becomes abnormally high, the pressure limiter operates (opens). It resumes operation (closes) after the pressure falls

to a certain level. Fuel released by the pressure limiter returns to the fuel tank.

< NOTE >

The operating pressures for the pressure limiter depend on the vehicle model and are approximately 140-230MPa for

the valve opening pressure, and approximately 30-50MPa for the valve closing pressure.

(2) Rail Pressure Sensor (Pc Sensor)

• The rail pressure sensor (Pc sensor) is installed on the rail. It detects the fuel pressure in the rail and sends a signal

to the engine ECU. This is a semi-conductor sensor that uses the piezo-electric effect of the electrical resistance vary-

ing when pressure is applied to a silicon element.

• There are also rail pressure sensors that have dual systems to provide a backup in case of breakdown. The output

voltage is offset.

Pressure Limiter

Leak

(To Fuel Tank)

Valve Open

Valve Close

Rail Pressure

Abnormally High Pressure

Return

Q000855E

GND

Vout

Sensor Wiring Diagram Common Rail Pressure Characteristic

Output Voltage

-

Rail Pressure

Outp

ut V

oltage

Vcc+5V

ECUPc

Vout Vcc=5V

GND Vout Vcc

Q000856E

Q000857E

E2S PR2 VCS

VC PR E2

PcSensors

VCVCS

PR2PR

E2E2S

+5V

ECU

ECU

Vout/VccVcc=5V

Rail Pressure

Ou

tpu

t V

olta

ge

1

Ou

tpu

t V

olta

ge

2


(3) Flow Damper

• The flow damper reduces the pressure pulsations of the fuel in the pressurized pipe and supplies fuel to the injectors

at a stabilized pressure. The flow damper also presents abnormal discharge of fuel by shutting off the fuel passage

in the event of excess fuel discharge, for example due to fuel leaking from an injection pipe or injector. Some flow

dampers combine a piston and ball, and some have only a piston.

Operation of Piston-and-Ball Type- When a pressure pulse occurs in a high-pressure pipe, the resistance of it passing through the orifice disrupts the

balance between the rail side and injector side pressures, so the piston and ball move to the injector side, absorbing

the pressure pulse. With normal pressure pulses, since the rail side and injector side pressures are soon balanced,

the piston and ball are pushed back to the rail side by the spring. If there is an abnormal discharge, for example

due to an injector side fuel leak, the amount of fuel passing through the orifice cannot be balanced out and the pis-

ton presses the ball against the seat, so the passage for fuel to the injector is shut off.

Operation of Piston-Only Type- The piston contacts the seat directly and the piston shuts off the fuel passage directly. Operation is the same as for

the piston-and-ball type.

Q000858E

Piston Ball

Seat Spring

Piston

Spring

Seat

Type Combining Piston and Ball Piston-Only Type

Q000859E

· During Pressure Pulse Absorption · Fuel Cut-Off

Piston Ball

SeatSpring

Q000860E

· During Pressure Pulse Absorption · Fuel Cut-Off

Piston

Spring

Seat


(4) Pressure Discharge Valve

• The pressure discharge valve controls the fuel pressure in the rail. When rail fuel pressure exceeds the target injection

pressure, or when the engine ECU judges that rail fuel pressure exceeds the target value, the pressure discharge

valve solenoid coil is energized. This opens the pressure discharge valve passage, allowing fuel to leak back to the

fuel tank, and reducing rail fuel pressure to the target pressure.

Q000861E


Rail

ON

ECU

To Fuel tank

Operating

Solenoid Coil


5. INJECTOR DESCRIPTION

5.1 General DescriptionThe injector injects the pressurized fuel in the rail into the engine combustion chamber at the optimal injection timing,

injection quantity, injection rate, and injection pattern, in accordance with signals from the ECU.

Injection is controlled using a TWV (Two-Way Valve) and orifice. The TWV controls the pressure in the control chamber

to control the start and end of injection. The orifice controls the injection rate by restraining the speed at which the nozzle

opens.

The command piston opens and closes the valve by transmitting the control chamber pressure to the nozzle needle.

When the nozzle needle valve is open, the nozzle atomizes the fuel and injects it.

There are three types of injectors: the X1, X2, and G2.

Q000862E

ECU

Supply Pump

Nozzle

Command Piston

Control Chamber Portion

Orifice

TWV

Rail


Nozzle Needle


5.2 Injector Construction and FeaturesThe injector consists of a nozzle similar to the conventional "nozzle & nozzle holder", an orifice that controls the injection

rate, the command piston, and a TWV (two-way solenoid valve). The basic construction is the same for the X1, X2, and

G2 types.

(1) X1 Type

• Precision control is attained through electronic control of the injection. The TWV comprises two valves: the inner valve

(fixed) and the outer valve (movable).

Q000863E

Nozzle

Command Piston

TWV

Solenoid

Orifice 1 Orifice 2

Inner Valve

Outer Valve


(2) X2 Type

• By reducing the injector actuation load, the injector has been made more compact and energy efficient, and its injec-

tion precision has been improved. The TWV directly opens and closes the outlet orifice.

Control

ChamberSolenoid

ValveHollow Screw with Damper

O-ring

Command Piston

Nozzle Spring

Pressure Pin

Nozzle Needle

Seat

High-Pressure FuelLeak Passage

From Rail

Q000864E


(3) G2 Type

• To ensure high pressure, the G2 type has improved pressure strength, sealing performance and pressure wear re-

sistance. It also has improved high-speed operability, enabling higher-precision injection control and multi-injection.

< NOTE >

Multi-injection means that for the purpose of reducing exhaust gas emissions and noise, the main injection is accom-

plished with one to five injections of fuel without changing the injection quantity.

Q000865E

Connector

Solenoid Valve

Command Piston

Nozzle Spring

Pressure Pin

Nozzle Needle

Seat Leak Passage

From Rail

To Fuel Tank

Example : Pattern with Five Injections

Time

Pre-InjectionPilot Injection After-Injection

Main Injection

Post-Injection

Inje

ctio

n Q

ua

ntity

Q000866E


5.3 Injector OperationThe injector controls injection through the fuel pressure in the control chamber. The TWV executes leak control of the

fuel in the control chamber to control the fuel pressure within the control chamber. The TWV varies with the injector type.

Non-Injection• When the TWV is not energized, the TWV shuts off the leak passage from the control chamber, so the fuel pressure

in the control chamber and the fuel pressure applied to the nozzle needle are both the same rail pressure. The nozzle

needle thus closes due to the difference between the pressure-bearing surface area of the command piston and the

force of the nozzle spring, and fuel is not injected. For the X1 type, the leak passage from the control chamber is shut

off by the outer valve being pressed against the seat by the force of the spring, and the fuel pressure within the outer

valve. For the X2/G2 types, the control chamber outlet orifice is closed directly by the force of the spring.

Injection• When TWV energization starts, the TWV valve is pulled up, opening the leak passage from the control chamber.

When this leak passage opens, the fuel in the control chamber leaks out and the pressure drops. Because of the drop

in pressure within the control chamber, the pressure on the nozzle needle overcomes the force pressing down, the

nozzle needle is pushed up, and injection starts. When fuel leaks from the control chamber, the flow quantity is re-

stricted by the orifice, so the nozzle opens gradually. The injection rate rises as the nozzle opens. As current continues

to be applied to the TWV, the nozzle needle eventually reaches the maximum amount of lift, which results in the max-

imum injection rate. Excess fuel is returned to the fuel tank through the path shown.

End of Injection• When TWV energization ends, the valve descends, closing the leak passage from the control chamber. When the

leak passage closes, the fuel pressure within the control chamber instantly returns to the rail pressure, the nozzle

closes suddenly, and injection stops.

Q000867E

Outer Valve

Injection Rate

Control Chamber Pressure



Solenoid

TWV

Outlet Orifice

Inlet Orifice

Command Piston

NozzleInjection Rate Injection Rate

Non-Injection Injection End of Injection

Rail

X1

X2 · G2

Outlet Orifice

Actuating Current

Actuating Current

Actuating Current

Inner Valve

To Fuel TankLeak Passage

Leak Passage

TWV


5.4 Injector Actuation CircuitIn order to improve injector responsiveness, the actuation voltage has been changed to high voltage, speeding up both

solenoid magnetization and the response of the TWV. The EDU or the charge circuit in the ECU raises the respective

battery voltage to approximately 110V, which is supplied to the injector by signal from the ECU to actuate the injector.

Q000868E

INJ#1 (No.1 Cylinder)

ECU

Injector




Charging Circuit

IJt

IJf

EDU

Actuating Current

ECU

Actuating Current

ECU Direct Actuation

EDU Actuation

2WV#3 (No.3 Cylinder)




Injector

Common 2

Common 1



Constant Amperage Circuit

High Voltage

Generation Circuit

Control

Circuit



High Voltage Generation Circuit


5.5 Other Injector Component Parts

(1) Hollow Screw with Damper

• The hollow screw with damper enhances injection quantity accuracy, by reducing the back-pressure pulsations (pres-

sure fluctuations) of the leak fuel. In addition, it minimizes the back-pressure dependence (the effect of the pressure

in the leak pipe changing the injection quantity even though the injection command is the same) of the fuel in the leak

pipe.

(2) Connector with Correction Resistor

• The connector with correction resistor has a built-in correction resistor in the connector section to minimize injection

quantity variation among the cylinders.

Q000869E

Hollow Screw with Damper

O-ring

O-ring

Damper

To Fuel tank

Q000870E

Correction Resistor Terminal

Solenoid Terminal


(3) Injector with QR Codes

• QR (Quick Response) codes have been adopted to enhance correction precision. The QR code, which contains the

correction data of the injector, is written to the engine ECU. QR codes have resulted in a substantial increase in the

number of fuel injection quantity correction points, greatly improving injection quantity precision.

< NOTE >

QR codes are a new two-dimensional code that was developed by DENSO. In addition to injection quantity correction

data, the code contains the part number and the product number, which can be read at extremely high speeds.

Q000871E

Inje

ctio

n Q

ua

ntity

Actuating Pulse Width TQ

Pressure Parameter

· QR Code Correction Points (Example)

10EA01EB13EA01EB

0300 00000000 BC

QR Codes

ID Codes


Handling Injectors with QR Codes (Reference) - Injectors with QR codes have the engine ECU recognize and correct the injectors, so when an injector or the engine

ECU is replaced, it is necessary to register the injector's ID code in the engine ECU.

Replacing the Injector- It is necessary to register the ID code of the injector that has been replaced in the engine ECU.

Replacing the Engine ECU- It is necessary to register the ID codes of all the vehicle injectors in the engine ECU.

QD1536E

Engine ECU

Spare Injector

"No correction resistance, so no electrical recognition capability."

* Necessary to record the injector ID codes in the Engine ECU.

"No correction resistance, so no electrical recognition capability."

* Necessary to record the injector ID codes in the Engine ECU.

Q000985E

Vehicle-Side Injector Spare Engine ECU


6. DESCRIPTION OF CONTROL SYSTEM COMPONENTS

6.1 Engine Control System Diagram (Reference)

Q000874E

Rail



Pressure Limiter

Injector

Engine ECU

EDU

E-VRV for EGR

EGR Shut-Off VSV


Cylinder Recognition Sensor (TDC (G) Sensor: HP2, 3, 4)


Intake Air Temperature SensorAirflow Meter

(with Intake Air Temperature Sensor)

Coolant Temperature Sensor


Ignition Switch Signal

Starter Signal

Warm-Up Switch Signal

Vehicle Speed Signal

Supply Pump

TDC(G) Sensor(HP0)

SCV(HP2·3·4)

Fuel Temperature Sensor (HP2·3·4)

PCV(HP0)

To Fuel Tank

Charge Circuit

Flow Damper (Large Vehicles)

PCV TDC (G) Sensor


SCV



SCV

SCV

Supply Pump

HP0 HP2 HP3 HP4

Fuel Temperature Sensor (HP0)

Flywheel


6.2 Engine ECU (Electronic Control Unit)The engine ECU constantly ascertains the status of the engine through signals from the sensors, calculates fuel injec-

tion quantities etc. appropriate to the conditions, actuates the actuators, and controls to keep the engine in an optimal

state. The injectors are actuated by either the EDU or the charge circuit in the engine ECU. This actuation circuit de-

pends on the specifications of the model it is mounted in. The ECU also has a diagnosis function for recording system

troubles.

6.3 EDU (Electronic Driving Unit)

(1) General Description

• An EDU is provided to enable high-speed actuation of the injectors. The EDU has a high-voltage generation device

(DC/DC converter) and supplies high voltage to the injectors to actuate the injectors at high speed.

Q000875E

Sensors Engine ECU Actuators


(TDC (G) Sensor)

Crankshaft Position Sensor

(Engine Speed Sensor)


Other Sensors

Engine ECU

Injector

Supply Pump

(PCV : HP0, SCV : HP2 · HP3 · HP4)

Other Actuators

Charge Circuit (Built into ECU)

or

EDU

Actuation Circuit

ECU EDU

Actuation Signal

Check Signal

Actuation Output

Q000876E


(2) Operation

• The high-voltage generating device in the EDU converts the battery voltage into high voltage. The ECU sends signals

to terminals B through E of the EDU in accordance with the signals from the sensors. Upon receiving these signals,

the EDU outputs signals to the injectors from terminals H through K. At this time, terminal F outputs the IJf injection

verification signal to the ECU.

6.4 Various SensorsVarious Sensor Functions

Sensor Functions

Crankshaft Position Sensor(Engine Speed Sensor)

Detects the crankshaft angle and outputs the engine speed signal.

Cylinder Recognition Sensor(TDC (G) Sensor)

Identifies the cylinders.

Accelerator Position Sensor Detects the opening angle of the accelerator pedal.

Intake Air Temperature Sensor Detects the temperature of the intake air after it has passed through the turbo-charger.

Mass Airflow Meter Detects the flow rate of the intake air. It also contains an intake air temperature sen-sor that detects the temperature of the intake air (atmospheric temperature).

Coolant Temperature Sensor Detects the engine coolant temperature.


Intake Air Pressure Sensor Detects the intake air pressure.

Atmospheric Pressure Sensor Detects the atmospheric pressure.

GND GND

High Voltage Generation Circuit

Control Circuit

A L

BIJt#1

IJt#1

COM+B

IJt#2

IJt#3

IJt#4

IJt#2

IJt#3

IJt#4

IJf

C

D

E

F

G M

H

I

J

K

ECU

Q000877E


(1) Crankshaft Position Sensor (Engine Speed Sensor) and Cylinder Recognition SensorTDC (G) Sensor

Crankshaft Position Sensor (Engine Speed Sensor)• The crankshaft position sensor is installed near the crankshaft timing gear or the flywheel. The sensor unit is a MPU

(magnetic pickup) type. When the engine speed pulsar gear installed on the crankshaft passes the sensor section,

the magnetic field of the coil within the sensor changes, generating AC voltage. This AC voltage is detected by the

engine ECU as the detection signal. The number of pulses for the engine speed pulsar depends on the specifications

of the vehicle the sensor is mounted in.

Cylinder Recognition Sensor TDC (G) Sensor• The cylinder recognition sensor is installed on the supply pump unit for the HP0 system, but for the HP2, HP3, or HP4

system, it is installed near the supply pump timing gear. Sensor unit construction consists of the MPU type, which is

the same as for the crankshaft position sensor, and the MRE (magnetic resistance element) type. For the MRE type,

when the pulsar passes the sensor, the magnetic resistance changes and the voltage passing through the sensor

changes. This change in voltage is amplified by the internal IC circuit and output to the engine ECU. The number of

pulses for the TDC pulsar depends on the specifications of the vehicle the sensor is mounted in.

Sensor Mounting Position (Reference)

NE+

NE-

VCC

TDC(G)

GND

TDC(G)TDC(G)-TDC(G)GNDVCC

NE

TDC (G) Pulse

TDC(G)

ECU

0V

360 CA 360 CA

720 CA

Engine Speed Pulsar TDC (G) Pulsar

Q000878E

Pulsar (Gearless Section)



Pulsar

For MPU Type

For MRE Type

MPU Type

MPUType

MRE Type

MRE Type

MPUType

MRE Type

External View of Sensor

ShieldedWire


Cylinder Recognition Sensor(TDC (G) Sensor)

TDC (G) Input Circuit

Engine SpeedInput Circuit

Circuit Diagram

Pulse Chart (Reference)

Engine Speed

Pulse


(2) Accelerator Position Sensor

• The accelerator position sensor converts the accelerator opening into an electric signal and outputs it to the engine

ECU. There are two types of accelerator position sensor: the hall element type and the contact type. In addition, to

provide backup in the event of breakdown, there are two systems and the output voltage is offset.

Hall Element Type- This sensor uses a hall element to generate voltage from change in the direction of the magnetic field. A magnet

is installed on the shaft that rotates linked with the accelerator pedal, and the rotation of this shaft changes the mag-

netic field of the Hall element. The voltage generated by this change in the magnetic field is amplified by an amplifier

and input to the engine ECU.

Contact Type- The sensor uses a contact-type variable resistor. Since the lever moves linked with the accelerator pedal, the sen-

sor resistance value varies with the accelerator pedal opening. Therefore, the voltage passing the sensor changes,

and this voltage is input to the engine ECU as the accelerator opening signal.

Q000879E

4

3

2

1

0 50 100VA

CC

P O

utp

ut

Vo

lta

ge

(V

)

Accelerator Opening (%)Hall Elements (2)

Magnets (Pair)

Amplifier No. 1

Amplifier No. 2

+5V

+5V

A-VCC

A-VCC

VACCP1

VACCP2

A-GND

A-GND

ECUAccelerator Pedal Accelerator Pedal

VPA2

VPA1

EP2 VPA2 VCP2 EP1 VPA1 VCP1

Accelerator Position Sensor Circuit Diagram

Ou

tpu

t V

olta

ge

Accelerator Pedal Position


Fully Open

Fully Open

FullyOpen

Q000880E

Fully Closed

Fully Closed

Fully Closed

Accelerator Position SensorOutput Voltage Characteristic


(3) Intake Air Temperature Sensor

• The intake air temperature sensor detects the temperature of the intake air after it has passed the turbocharger. The

sensor portion that detects the temperature contains a thermistor. The thermistor, which has an electrical resistance

that changes with temperature, is used to detect the intake air temperature.

(4) Mass Airflow Meter (with Built-In Intake Air Temperature Sensor)

• The mass air flow meter is installed behind the air cleaner and detects the intake air flow (mass flow). This sensor is

a hot-wire type. Since the electrical resistance of the hot wire varies with the temperature, this characteristic is utilized

to measure the intake air quantity. The mass airflow meter also has a built-in intake air temperature sensor (thermistor

type) and detects the intake air temperature (atmospheric temperature).

(5) Coolant Temperature Sensor

• The coolant temperature sensor is installed on the cylinder block and detects the coolant temperature. This sensor is

a thermistor type.

Thermistor

Q000881E

Re

sis

tan

ce

Temperature

Resistance - TemperatureCharacteristic

E2THAFVGE2G+B

Temperature

Temperature Characteristic

C ( F)

Intake Air TemperatureSensor

Hot Wire

Q000882E

Resis

tance

Intake Air Temperature Sensor Resistance

-

Q000883E

Coolant Temperature

Resis

tance V

alu

e+5V

VTHW

A-GND

ECU

Thermistor

Coolant TemperatureSensor Resistance

Water TemperatureCharacteristic

-


(6) Fuel Temperature Sensor

• This is a thermistor type sensor that detects the fuel temperature. In the HP2, HP3, and HP4 systems, this sensor is

installed on the supply pump unit, but in the HP0 system, it is installed on a leak pipe from an injector.

(7) Intake Air Temperature Sensor and Atmospheric Pressure Sensor

• This sensor is a semiconductor type sensor. It measures pressure utilizing the piezoelectric effect that when the pres-

sure on the silicon element in the sensor changes, its electrical resistance changes. In addition, the air pressure on

this sensor is switched between the pressure within the intake manifold and the atmospheric pressure, so both the

intake air pressure and the atmospheric pressure are detected with one sensor. The switching between intake air

pressure and atmospheric pressure is handled by the VSV (vacuum switching valve). When any one of the conditions

below is established, the VSV is switched ON for 150 msec. by command of the engine ECU to detect the atmospheric

pressure. When none of the conditions below is established, the VSV is switched OFF to detect the intake air pres-

sure.

Atmospheric Pressure Measurement Conditions- Engine speed = 0 rpm

- Starter ON

- Stable idling state


Temperature

Re

sis

tan

ce

Va

lue

Thermistor

Q000848E

Q000885E

VC PIM E2

Absolute Pressure

PIM Output Voltage - Pressure

Characteristic

Ou

tpu

t V

olta

ge


7. CONTROL SYSTEM

7.1 Fuel Injection Control


• This system effects more appropriate control of the fuel injection quantity and injection timing than the mechanical

governor or timer used in the conventional injection pump. The engine ECU performs the necessary calculations

based on the signals that are received from the sensors located on the engine and the vehicle. Then, the ECU controls

the timing and duration of the current that is applied to the injectors in order to obtain optimal injection timing and

injection quantity.

(2) Various Types of Fuel Injection Controls

Control Functions

Fuel Injection Quantity Control This control replaces the function of the governor in the conventional injectionpump. It achieves optimal injection quantity by effecting control in accordance withthe engine speed and accelerator opening signals.

Fuel Injection Timing Control This control replaces the function of the timer in the conventional injection pump. Itachieves optimal injection timing by effecting control in accordance with theengine speed and the injection quantity.

Fuel Injection Rate Control (Pilot Injection Control)

This function controls the ratio of the fuel quantity that is injected from the orifice ofthe injector within a given unit of time.

Fuel Injection Pressure Control This control uses the rail pressure sensor to measure the fuel pressure, and itfeeds this data to the engine ECU in order to control the pump discharge quantity.


(3) Fuel Injection Quantity Control

General Description• This control determines the fuel injection quantity by adding coolant temperature, fuel temperature, intake air temper-

ature, and intake air pressure corrections to the basic injection quantity. The engine ECU calculates the basic injection

quantity based on the engine operating conditions and driving conditions.

Injection Quantity Calculation Method• The calculation consists of a comparison of the following two values: 1. The basic injection quantity that is obtained

from the governor pattern, which is calculated from the accelerator position and the engine speed. 2. The injection

quantity obtained by adding various types of corrections to the maximum injection quantity obtained from the engine

speed. The lesser of the two injection quantities is used as the basis for the final injection quantity.

Q000887E

Engine Speed

Engine Speed

Accelerator Opening

Inje

ctio

n

Qu

an

tity

Inje

ctio

n

Qu

an

tity

Accelerator Opening

Engine Speed

Basic Injection Quantity

Maximum Injection Quantity

Low Quantity

Side Selected

Corrected Final Injection

Quantity

Injector Actuation

Period Calculation

Individual Cylinder Correction Quantity

Intake Air Pressure Correction

Atmospheric Pressure Correction

Cold Engine Maximum Injection Quantity Correction

Ambient Temperature Correction

Intake Air Temperature Correction

Speed Correction

Injection Pressure Correction


Set Injection Quantities• Basic Injection Quantity

This quantity is determined by the engine speed and the accelerator opening. With the engine speed constant, if the

accelerator opening increases, the injection quantity increases; with the accelerator opening constant, if the engine

speed rises, the injection quantity decreases.

• Starting Injection Quantity

This is determined based on the basic injection quantity for when the engine starts up and the added corrections for

the starter S/W ON time, the engine speed, and the coolant temperature. If the coolant temperature is low, the injec-

tion quantity is increased. When the engine has completely started up, this mode is cancelled.

• Injection Quantity for Maximum Speed Setting

Determined by the engine speed. The injection quantity is restricted to prevent an excessive rise in engine speed

(overrun).

Ba

sic

In

jectio

n Q

ua

ntity

Engine Speed

Accelerator Opening

Q000888E

Inje

ctio

n Q

ua

ntity

STA ON Time

STA ON Starting

Starting Base InjectionQuantity

Coolant Temperature

High Low

Q000889E

Inje

ctio

n Q

ua

ntity

Engine Speed

Injection Quantity

for Maximum Speed Setting

Q000890E


• Maximum Injection Quantity

This is determined based on the basic maximum injection quantity determined by the engine speed, and the added

corrections for coolant temperature, fuel temperature, intake air temperature, atmospheric temperature, intake air

pressure, atmospheric pressure, and full Q adjustment resistance (only for the 1st generation HP0 system), etc.

Corrections• Cold Engine Maximum Injection Quantity Correction

When the coolant temperature is low, whether during start-up or during normal operation, this correction increases

the injection quantity.

• Intake Air Pressure Correction

When the intake air pressure is low, the maximum injection quantity is restricted in order to reduce the emission of

black smoke.

QB0717E

Engine Speed

Ba

sic

Ma

xim

um

In

jectio

n Q

ua

ntity

Inje

ctio

n Q

ua

ntity

Engine SpeedQ000891E

Q000892E

Engine Speed

Intake Air Pressure Correction Quantity

Inje

ctio

n Q

ua

ntity


• Atmospheric Pressure Correction

The maximum injection quantity is increased and decreased according to the atmospheric pressure. When the atmo-

spheric pressure is high, the maximum injection quantity is increased.

• Injection Quantity Delay Correction for Acceleration

During acceleration, if there is a large change in the accelerator pedal opening, the injection quantity increase is de-

layed in order to prevent black smoke emissions.

• Full Q Adjustment Resistance (Only for 1st Generation HP0 Systems)

The full Q resistance is for correcting the injection quantity for a full load. The maximum injection quantity is increased

or decreased by the car manufacturer to match to standards. There are 15 types of full Q adjustment resistance. The

appropriate one is selected and used.

Q000893E

Engine Speed

Atmospheric PressureCorrection Quantity

Inje

ctio

n Q

ua

ntity

Q000487E

Time

Change in Accelerator Pedal Position

Injection QuantityAfter Correction

Delay

Inje

ctio

n Q

ua

ntity

+5V

ECU

VLQC

A-GND

Quantity Adjustment Resistor Correction Voltage

Quantit

y A

dju

stm

ent

Corr

ect

ion Inje

ctio

n Q

uantit

y


(4) Fuel Injection Rate Control

• Although the injection rate increases with the adoption of high-pressure fuel injection, the ignition lag, which is the

delay from the start of injection to the beginning of combustion, cannot be shortened to less than a certain period of

time. Therefore, the quantity of fuel injected until ignition takes place increases (the initial injection rate is too high),

resulting in explosive combustion simultaneous with ignition, and an increase in NOx and sound. To counteract this

situation, pilot injection is provided to keep the initial injection at the minimum requirement rate, to dampen the primary

explosive combustion, and to reduce NOx and noise.

Q000895E

Injection Rate

Heat Release Rate

Large First-StageCombustion

Small First-StageCombustion

Crankshaft Angle (deg) Crankshaft Angle (deg)

-20 TDC 20 40 -20 TDC 20 40

[Ordinary Injection] [Pilot Injection]


(5) Fuel Injection Timing Control

• The fuel injection timing is controlled by the timing of the current applied to the injectors. After the main injection period

is decided, the pilot injection and other injection timing is determined.

Main Injection Timing- The basic injection timing is calculated from the engine speed (engine speed pulse) and the final injection quantity,

to which various types of corrections are added in order to determine the optimal main injection timing.

Pilot Injection Timing (Pilot Interval)- Pilot injection timing is controlled by adding a pilot interval value to the main injection. The pilot interval is calculated

based on the final injection quantity, engine speed, coolant temperature, atmospheric temperature, and atmospher-

ic pressure (map correction). The pilot interval at the time the engine is started is calculated from the coolant tem-

perature and engine speed.

Q000896E

Actual Top Dead Center

Pilot Injection Main Injection

Pilot Injection Timing

Pilot Interval

Main Injection Timing

1. Outline of Injection Timing Control Timing

2. Injection Timing Calculation Method

Engine Speed

Injection Quantity

Basic InjectionTiming

Correction

Main Injection Timing

Battery Voltage Correction

Intake Air Pressure Correction

Atmospheric Pressure Correction

Intake Air Temperature Correction

Coolant Temperature Correction

Pilot Interval Basic InjectionTiming

Pilot

Interva

l

Engine Speed

Basic

Inject

ion T

iming

PilotInjection Timing

NE

INJ

lift

10

Engine Speed

Engine Speed Pulse

Injector Solenoid ValveControl Pulse

Nozzle NeedleLift


Split Injection- The purpose of split injection is to improve the startability of a cold engine. Before the conventional main injection

takes place, this function injects two or more extremely small injections of fuel.

Multi-Injection Control (Only for Some Models)- Multi-injection control is when small injections (up to four times) are carried out before and after the main injection

in accordance with the state of the main injection and engine operation. This interval (the time A-D in the diagram

below) is based on the final injection quantity, engine speed, coolant temperature, and atmospheric pressure (map

correction). The interval during start-up is based on the coolant temperature and engine speed.

(6) Fuel Injection Pressure Control

• The engine ECU calculates the fuel injection pressure, which is determined by the final injection quantity and the en-

gine speed. The calculation is based on the coolant temperature and engine speed during start-up.

Q000897E

Main Injection Main Injection

Pilot Injection

Pilot Injection

Pilot Injection

Multi-Injection

This is the same as conventional

fuel injection.

Before the main injection, a small

quantity of fuel is injected.

If the temperature is low when the engine

starts, a small quantity of fuel is injected

divided over multiple injections before the

main injection.

Pre-Injection

Q000898E

TDC

A C DB

TDC (G) Pulse

Injection Rate

Q000899EEngine Speed

Final Injection Quantity

Rail

Pre

ssure


(7) Other Injection Quantity Control

Idle Speed Control (ISC) System• The idle speed control system controls the idle speed by regulating the injection quantity in order to match the actual

speed to the target speed calculated by the computer. The ISC can be automatic ISC or manual ISC.

Automatic ISC- With automatic ISC, the engine ECU sets the target speed. The target engine speed varies with the type of trans-

mission (automatic or manual), whether the air conditioner is ON or OFF, the shift position, and the coolant temper-

ature.

Idle Speed Control Conditions

Conditions When Control Starts Conditions Affecting Control

· Idle Switch

· Accelerator Opening

· Vehicle Speed

· Water Temperature

· Air Conditioning Load

· Shift Position

Engine ECU

Target Engine Speed Calculation Comparison

Fuel injection Quantity Correction

Actual Engine Speed

ActuatorsFuel Injection Quantity Instruction

Q000900E


Manual ISC- The idle engine speed is controlled by the setting on the idle setting button at the driver's seat.

Idle Vibration Reduction Control- This control reduces engine vibration during idle. To achieve smooth engine operation, it compares the angle

speeds (times) of the cylinders and regulates injection quantity for each individual cylinder in the event of a large

difference.

ECU

A-GND

V-IMC

A-VCC+5V

IMC Volume Terminal Voltage

Q000901E

Ta

rge

t E

ng

ine

Sp

ee

d

Q000902E

t4 t3 t1

#1 #3 #4

#1 #1 #3 #4 #2#3 #4 #2

(Make the t for all the cylinders equal.)

Angular Speed

Crankshaft Angle Crankshaft AngleCorrection


7.2 E-EGR System (Electric-Exhaust Gas Recirculation)


• The E-EGR system is an electronically controlled EGR system. The EGR system recirculates a portion of the exhaust

gases into the intake manifold in order to lower the combustion chamber temperature and reduce NOx emissions.

However, operation of the EGR system may reduce engine power output and affect drivability. For this reason, in the

E-EGR system, the engine ECU controls the EGR to achieve an optimal EGR amount.

Operation Conditions Example- This operates in the operation region fulfilling the starting conditions below (one example).

(2) Operation

• After the vacuum pump generates a vacuum, the E-VRV (electric-vacuum regulation valve) regulates the vacuum and

directs it to the diaphragm chamber of the EGR valve. In response to this vacuum, the diaphragm pushes the spring

downward, which determines the opening of the EGR valve and controls the EGR volume.

• The EGR cooler, which is provided in the EGR passage between the cylinder head and the intake passage, cools the

EGR in order to increase the EGR volume.

• The EGR cutoff VSV, which opens the diaphragm chamber to the atmosphere when the EGR valve is closed, helps

to improve response.

Inje

ction Q

uantity

Engine Speed

· Engine Operating Conditions

· · · · · Except during engine warm-up and startup,

does not overheat, etc.

· EGR Operating Range

· · · · · · · · For Engine Medium Load

Q000501E

Q000903E

EGR Cooler

EGR Valve

Coolant

Diaphragm

Vacuum Damper

Spring

EGR Shut-Off VSV

Vacuum Pump

E-VRV

Control Unit

Engine Speed

Accelerator Opening

Intake Air Pressure AndAtmospheric Pressure

Coolant Temperature

Intake Air

Relationship Between Vacuum and EGR Valve Opening

Low

Small

High

Large

Vacuum

EGR Valve Opening

Engine

ExhaustManifold


To Increase the EGR Quantity- The E-VRV duty ratio is controlled*1. In the stable condition shown in the bottom center diagram, an increase in the

current that is applied to the coil causes the attraction force FM in the coil to increase. When this force becomes

greater than the vacuum force FV that acts on the diaphragm, the moving core moves downward. Along with this

movement, the port from the vacuum pump to the upper chamber of the diaphragm opens. Consequently, the out-

put vacuum increases, which causes the EGR valve to open and the EGR volume to increase. Meanwhile, because

"increased output vacuum equals increased FV", the moving core moves upward with the increase in FV. When

FM and FV are equal, the port closes and the forces stabilize. Because the vacuum circuit of the EGR is a closed

loop, it maintains the vacuum in a stabilized state, provided there are no changes in the amperage.

< NOTE >*1 : The engine ECU outputs sawtooth wave signals with a constant frequency. The value of the current is the effective (average) value of these

signals. For details, see the explanation of the HP3 supply pump and SCV.

To Decrease the EGR Volume- A decrease in the current that is applied to the coil causes FV to become greater than FM. As a result, the dia-

phragm moves upward. The moving core also moves upward in conjunction with the movement of the diaphragm,

causing the valve that seals the upper and lower diaphragm chambers to open. Consequently, the atmospheric

pressure in the lower chamber enters the upper chamber, thus reducing the output vacuum. This causes the EGR

valve to close and the EGR volume to decrease. Because "decreased output vacuum equals decreased FV", the

moving core moves downward with the decrease in FV. When FM and FV are equal, the port closes and the forces

stabilize.

FV

FM

FM > FV

EGR Quantity Increased

FM < FV

EGR Quantity Decreased

To EGR Valve

From Vacuum Pump

Atmosphere

Valve

Spring

Coil

Stator Core

Diaphragm

Moving Core

Q000904E


7.3 Electronically Controlled Throttle (Not Made By DENSO)


• The electronically controlled throttle is located upstream of the EGR valve in the intake manifold. It controls the throttle

valve at an optimal angle to regulate the EGR gas and reduce noise and harmful exhaust gases.

(2) Operation

• Signals from the engine ECU actuate the stepping motor, which regulates the throttle valve opening.

EGR Control• To further increase the EGR volume when the EGR valve is fully open, the vacuum in the intake manifold can be in-

creased by reducing the throttle valve opening, which restricts the flow of the intake air.

Noise and Exhaust Gas Reduction• When the engine is being started, the throttle valve opens fully to reduce the emissions of white and black smoke.

• When the engine is being stopped, the throttle valve closes fully to reduce vibration and noise.

• During normal driving, the throttle valve opening is controlled in accordance with the engine conditions, coolant tem-

perature, and atmospheric pressure.

Stepping Motor

Throttle Valve

Q000905E


7.4 Exhaust Gas Control System


• The exhaust gas control system is provided to improve warm-up and heater performance. This system actuates the

exhaust gas control valve VSV, which is attached to the exhaust manifold. It increases the exhaust pressure to in-

crease the exhaust temperature and engine load, in order to improve warm-up and heater performance.

(2) Operation

• The exhaust gas control system operates when the warm-up switch is ON, and all the conditions listed below have

been met.

Operation Conditions- The EGR is operating.

- The coolant temperature is below 70°C.

- The ambient temperature is below 5°C.

- A minimum of 10 seconds have elapsed after starting the engine.

- The engine speed and fuel injection quantity are in the state shown in the graph below.

Air Cleaner

Exhaust Gas Control Valve

Exhaust Gas Control Valve

Vacuum Pump

VSV

Turbo PressureSensor

Coolant TemperatureSensor

EGR Valve PositionSensor

Warm-Up Switch

Mass Airflow Meter


AcceleratorPosition Sensor

AtmosphericPressure Sensor

ECU

Q000906E

Q000907E

WARM UP

Engine Speed

Operating Range

Extremely Low Torque or Engine Speed Range

[Exhaust Gas Control System Operating Range]

Inje

ction Q

uantity


7.5 DPF System (Diesel Particulate Filter)


• This system reduces emissions of PM (particulate matter). In order to collect PM, a DPF cleaner with built-in catalytic

filter is mounted on the center pipe. The collected PM is handled with combustion processing during operation.

(2) System Configuration

(3) Various Sensors

Exhaust Gas Temperature Sensor• The exhaust gas temperature sensor is installed to the front and rear of the DPF to detect the temperature in these

positions. The engine ECU controls the exhaust temperature for PM combustion based on the signals from this sen-

sor. The sensor element is a thermistor.

Q000908E

Rail

G2 InjectorIntercooler

VNT Actuator

EquilibriumActuator

EGR Cooler

Intake AirPressure Sensor

EGR Valve

Supply Pump

DPF (with Oxidation Catalyst)

Exhaust Gas Temperature Sensor

Exhaust Gas Temperature Sensor

Differential Pressure Sensor

ECU & EDU

Q000909EExhaust Gas Temperature ( )

Thermistor Element

Cover

Re

sist

an

ce V

alu

e (

)


Differential Pressure Sensor• The differential pressure sensor detects the difference in pressure at the front and rear of the DPF, and outputs a sig-

nal to the engine ECU. The sensor portion is a semiconductor type pressure sensor that utilizes the piezoelectric ef-

fect through a silicon element, and amplifies and outputs the voltage with its IC circuit. When PM is collected and

accumulated in the DPF, the filter clogs and the difference in pressure at the front and rear of the DPF increases.

Therefore, based on the signals from this sensor, the engine ECU judges whether or not to subject PM to combustion

processing.

(4) Operation

• By optimizing the injection pattern and controlling the exhaust gas temperature based on the exhaust gas temperature

and the difference in pressure at the front and rear of the DPF, PM is collected, oxidized, and self-combusted. When

the exhaust temperature is low, adding after-injection after the main injection raises the exhaust gas temperature to

approximately 250?C and promotes oxidation of the PM. When the PM is collected and accumulated, the post-injec-

tion is added and HC is added to the catalyst to raise the catalyst temperature to 600?C, which is the self-combustion

temperature for PM. This combusts the accumulated PM in a short time. The engine ECU controls the A, B, and C

times and the injection times.

Q000910E

GND

VP

VC

Pressure (kPa)

Outp

ut V

oltage

VP

(V)

TDC A

B CAfter-Injection Post-Injection

Q000506E


7.6 DPNR SYSTEM (DIESEL PARTICULATE NOx REDUCTION)


• This system reduces the emissions of PM (particulate matter) and NOx. The DPNR catalyst mounted in the center

pipe collects and regenerates PM and reduces NOx all at the same time. The collected PM is handled with combus-

tion processing during operation.

(2) System Configuration

Q000911E

Supply Pump Exhaust Gas CleaningDevice Switch

Exhaust Gas CleaningDevice Display Lamp

Injector

DPNR Catalyst

Oxidation Catalyst

A/F Sensor

Exhaust Gas Temperature SensorDifferential Pressure SensorNSR

A/F Sensor

Fuel Addition Valve

Oxidation Catalyst Before EGR Cooler

Engine ECU

Exhaust Retarder VSV

Exhaust Retarder

Intake Restriction Valve


8. DIAGNOSIS

8.1 Outline Of The Diagnostic FunctionThe diagnostic function enables a system to self-diagnose its own malfunctions. If abnormal conditions occur in the sen-

sors or actuators used in the control systems, the respective systems convert the malfunction signals into codes and

transmit them to the engine ECU. The engine ECU records the transmitted malfunction code into memory. Recorded

codes are output at the diagnostics connector on the vehicle. To inform the driver of the malfunction, the engine ECU

causes the MIL (Malfunction Indicator Light) in the meter to illuminate. Accurate troubleshooting can be performed by

way of the DTCs (Diagnostic Trouble Codes) that are output at the diagnostic connector. For details on actual diagnosis

codes, see the vehicle manual. It is necessary to put the vehicle into the state below before starting inspection.

(1) Pre-Inspection Preparation

• Position the shift lever in "N" or "P".

• Turn OFF the air conditioner.

• Verify that the throttle valve is fully closed.

8.2 Diagnosis Inspection Using DST-1The DST-1 can be used in both normal and check modes. Compared to the normal mode, the check mode has a higher

sensitivity to detect malfunctions.

The check mode inspection is performed when normal codes are output in the normal mode, despite the fact that there

may be malfunctions in the sensor signal systems.

(1) Reading DTCs

1) DST-1 Connection: Connect the DST-1 to the DLC3 termi-

nal.

2) Reading DTCs: Operate in accordance with the instructions

shown on the screen to display the "DTC check" screen. Se-

lect either the normal or check mode and read the DTC.

< NOTE >

If no DTC appears on the screen, there may be a failure

in the engine ECU.

16 15 14 13 12 11 10 9

8 7 6 5 4 3 2 1

DLC3

Q000914

Diagnostic Trouble Codes (DTC)

1. · · ·

Execute: Execute Q000915E


3) Checking the Freeze Frame Data: If the symptom that out-

puts a DTC cannot be duplicated, check the freeze frame

data.

4) Erasing DTCs from memory: Operate in accordance with

the instructions shown on the screen to display the "DTC

check" screen. Select "Erase DTCs" to erase the DTCs.

< NOTE >

If it is not possible to erase the DTC, turn the ignition

switch OFF, and repeat the process.

5) Wiring Harness and Connector Open Circuit Check

< NOTE >

If the DTC output during a diagnostic inspection (in the

check mode) has identified the system with a malfunction,

use the method indicated below to narrow down the area

of the malfunction.

• Erasing DTCs from memory: After reading the DTCs in check mode, erase the DTCs from memory.

• Starting the Engine: Select the check mode and start the engine.

• Malfunctioning system check 1: While the engine is running at idle, shake the wiring harness and connectors of the

system that output the malfunction during the diagnosis (check mode) inspection.

• Malfunctioning system check 2: If the MIL (Malfunction Indicator Light) illuminates when the wiring harness and con-

nectors are shaken, there is a poor contact in the wiring harness or connectors in that area.

8.3 Diagnosis Inspection Using The MIL (Malfunction Indicator Light)Before reading a DTC, turn the ignition switch ON to make sure the MIL (Malfunction Indicator Light) illuminates.

Inspections in the check mode cannot be performed.

(1) Reading DTCs

Short circuiting the connector• Using the STT, short circuit between DLC1 terminals 8 (TE1) and 3 (E1) or between DLC3 terminals 13 (TC) and 4

(CG).

< CAUTION >

Never connect the wrong terminals of the connectors as this will lead to a malfunction.

Q000916E

This will erase the DTC and freeze frame data.

Do you wish to proceed?

DTC (ECD Erasure)

NG : - OK : +

4

TE1

E1

TC

CG

1 2 3 5 6 18

7 8 9 10 11 20

12 13 14 15 16 17 21 22 23

1916 15 14 13 12 11 10 9

8 7 6 5 4 3 2 1

DLC1 DLC3

Q000917E


Reading DTCs 1• Turn the ignition switch ON and count the number of times the MIL (Malfunction Indicator Light) blinks

< NOTE >

• If the MIL (Malfunction Indicator Light) does not output a code (the light does not blink), there may be an open circuit in

the TC terminal system or a failure in the engine ECU.

• If the malfunction indicator light is constantly ON, there may be a short (pinching) in the wiring harness or a failure in

the engine ECU.

• If meaningless DTCs are output, there may be a malfunction in the engine ECU.

• If the MIL (Malfunction Indicator Light) illuminates without outputting a DTC while the engine operates at a minimum

speed of 1000rpm, turn the ignition switch OFF once; then resume the inspection.

Reading DTCs 2• If an abnormal DTC has been output, check it against the DTC list.

Erasing DTCs from memory• Remove the ECD fuse (15A); after 15 seconds have elapsed, re-install the fuse.

< CAUTION >

After completing the inspection of the ECD system, erase the DTC memory, and make sure the normal code is output.

0.26sec 0.26sec

0.26sec

ON

OFF

ON

OFF

0.52sec 1.5sec 2.5sec 1.5sec 4.5sec

4.5sec

0.52sec 0.52sec

· Normal Operation

· Malfunction (Codes "12" and "23" are output.)

Jump Terminals TE1 and TC

Jump Terminals TE1 and TC

Repeat

Repeat Thereafter

MalfunctionIndicator Light

Q000918E

ECD Fuse (15A)

Engine Compartment Relay Block

Q000919E


8.4 Throttle Body Function Inspection< CAUTION >

• Be sure to inspect the function of the throttle body after it has been disassembled and reassembled, or after any of its

components have been removed and reinstalled.

• Verifying Throttle Motor: Verify that the motor generates an operating sound when the ignition switch is turned ON.

Also, verify that there is no interference sound.

(1) Erasing DTCs

1) Connect the DST-1 to the DLC3 connector.

2) Operate in accordance with the instructions shown on the

screen to display the "DTC check" screen. Select "Erase

DTCs" to erase the DTCs.

(2) Inspection

• Start the engine and make sure the MIL (Malfunction Indicator Light) does not illuminate and the engine speed is with-

in standards when the air conditioner is turned ON and OFF after the engine has warmed up.

< CAUTION >

Make sure no electrical load is applied.

(3) Final Inspection

• After inspecting the throttle body function, drive test the vehicle to confirm that operation is normal.

16 15 14 13 12 11 10 9

8 7 6 5 4 3 2 1

DLC3

Q000914

Q000916E



DTC (ECD Erasure)

NG : - OK : +


9. END OF VOLUME MATERIALS

9.1 Particulate Matter (PM)At high concentration levels, this substance is known to affect the respiratory system. It consists of soluble organic mat-

ter such as unburned oil, unburned diesel fuel, and other "soluble organic matter" in the exhaust gases, and insoluble

organic matter such as soot (black smoke) and sulfuric acid gas.

9.2 Common Rail Type Fuel Injection System Development History AndThe World’s Manufacturers

The conventional injection pump faced certain issues such as injection pressure that depended on engine speed, and

limits on the maximum fuel pressure. Other types of injection control such as pilot injection also faced some difficulties.

Addressing these issues in a revolutionary manner, DENSO led the world by introducing a commercial application of

the common rail fuel injection system.

Two types of common rail fuel injection systems are in use today. One is the common rail system that pressurizes the

fuel and injects it directly into the cylinders. DENSO was the first in the world to introduce a commercial application of

this system. This system, which is undergoing further development, has been adopted in passenger car applications.

Other companies, such as R. Bosch, Siemens, and Delphi also offer their commercial versions of this system today. The

other system is the Hydraulic Electric Unit Injection (HEUI) system, which was developed by Caterpillar in the United

States. This system uses pressurized engine oil to pressurize the fuel by actuating the piston of the nozzle (injector)

through which the pressurized fuel is injected.


9.3 Higher Injection Pressure, Optimized Injection Rates, Higher InjectionTiming Control Precision, Higher Injection Quantity Control Precision

(1) Higher Injection Pressure

• The fuel that is injected from the nozzle turns into finer particles as the fuel injection pressure increases. This improves

combustion and reduces the amount of smoke contained in the exhaust gases. Initially, the maximum injection pres-

sure of the in-line pump (A type) and the distributor pump (VE type) was 60 MPa. Due to advancement in high-pres-

sure applications, there are some recently developed fuel injection systems that inject fuel at a pressure of 100 MPa

or higher. The second-generation common rail system injects fuel at an extremely high pressure of 180 MPa.

(2) Optimized Injection Rates

• The injection rate is the ratio of the changes in the fuel quantity that is injected successively from the nozzle within a

given unit of time.

Q000920E

50

Common Rail Series

100 150 200

185

145

120

120ECD V Series

Mechanical Pump

Injection Pressure (MPa)

A Type Pump

Distributor Type Pump

NB Type Pump

ECD V4 Pump

HP0Pump

HP2Pump

HP3,4Pump

ECD V3 Pump

(1st Generation)

(2nd Generation)

1 MPa is

approximately 10.2kgf/cm2

t

Injection Rate High Injection Rate

Inje

ctio

n Q

ua

ntity

Q000921E


• As the injection pressure increases, the injection rate increases accordingly. The increase in injection rate leads to an

increase in the volume of the air-fuel mixture that is created between the start of injection until ignition (the ignition lag

period). Because this mixture is subsequently combusted at once, it creates noise (diesel knock) and NOx. For this

reason, it is necessary to appropriately control the injection rate by maintaining a low injection rate at the beginning

of injection and supplying a sufficient quantity after the ignition. To meet this need, two-spring nozzles have been

adopted and a pilot injection system has recently been developed.

(3) Higher Injection Timing Control Precision

• Reducing exhaust gas emissions and fuel consumption and optimizing the injection timing are important. It is ex-

tremely difficult to achieve the desired exhaust emission reduction levels through methods that adjust the injection

timing according to speed (or centrifugal force), such as the conventional mechanical timer. For this reason, electron-

ically controlled systems have been adopted to freely and precisely control the injection timing in accordance with the

engine characteristics.

(4) Higher Injection Quantity Control Precision

• Power output adjustment in a diesel engine is accomplished by regulating the fuel injection quantity. Poor injection

quantity control precision leads to increased exhaust gas emissions, noise, and poor fuel economy. For this reason,

electronically controlled systems have been developed to ensure high precision injection quantity control.

2-Spring Nozzle

Injection Rate

Common Rail System

Injection Rate Control

Inje

ctio

n Q

ua

ntity

Inje

ctio

n Q

ua

ntity

Pilot Injection

Q000922E

Electronic Control Type Mechanical Timer

Engine Speed Engine Speed

Injection Quantity

Injection Quantity

Ad

va

nce

An

gle

Ad

va

nce

An

gle

Q000923E


9.4 Image Of Combustion Chamber InteriorWith conventional injection methods, because an excessive quantity of fuel was injected in the initial period, the explo-

sion pressure rose excessively, leading to the generation of noise such as engine knocking sounds. To improve this

condition through pilot injection, initially only the necessary and adequate quantity of fuel is injected. At the same time,

the combustion chamber temperature is raised, and main injection combustion is assisted while working to prevent

noise and vibration.

Conventional Injection Pilot Injection

Q000924E

Repair Section2–91

1. DIESEL ENGINE MALFUNCTIONS AND DIAGNOSTIC METH-ODS (BASIC KNOWLEDGE)

1.1 Combustion State and Malfunction CauseDepending on the state of combustion in a diesel engine, diesel knock as well as the color of the exhaust gas may

change. Subsequently, the cause of engine malfunctions can be ascertained from changes in diesel knock and exhaust

gas color.

(1) Diesel Knock

• When fuel mixed with air during the ignition lag period (from the time injection begins until the fuel is ignited) reaches

ignition temperature, the mixture is combusted in one burst. The pressure in the combustion chamber at this time rises

as the quantity of the air-fuel mixture increases. If a large amount of air-fuel mixture is created during the ignition lag

period, the pressure in the combustion chamber will rise rapidly. The pressure waves resulting from fuel ignition vi-

brate the cylinder walls and engine components, which generates noise. The generated noise is called "knocking".

To some extent, knocking is unavoidable in engines that use a self-ignition system.

Cause of Diesel Knocking

1 Early Injection TimingA large quantity of air-fuel mixture is created prior to ignition, or thecetane value is high.

2 Cold Engine

Ignition occurs late without an increase in temperature.3 Intake air temperature is low.

4 Poor Engine Compression

5 Poor Fuel Combustibility Ignition occurs late (low cetane value.)

Q002310E

KnockingSound

BlackSmoke

WhiteSmoke

Q002311E

Cylin

der

Inte

rnal P

ressure

Crankshaft AngleT.D.C.

Start ofInjection

Ignition

Pressure Increase


(2) White Smoke

White smoke: Uncombusted fuel that has been vaporized and then discharged.• White smoke is generated when combustion occurs at a relatively low temperature, resulting in the exhaust of un-

combusted fuel and oil particles. White smoke is most likely to be generated when combustion chamber temperature

is low.

Source of White Smoke

(3) Black Smoke

Black smoke: Fuel that has been baked into soot and discharged. • Black smoke is often referred to as just "smoke". Black smoke is generated when the injected fuel is poor in oxygen.

As the fuel is exposed to high temperatures, thermal breakdown occurs, leaving carbon behind. Black smoke occurs

when the injected fuel quantity is too large, or when the air-fuel mixture is rich due to an insufficient quantity of air.

Source of Black Smoke

1.2 TroubleshootingTroubleshooting cautions

Observe the following cautions to avoid decreased engine performance and fuel injector malfunctions.

• Use the designated fuel.

• Avoid water and foreign material intrusion into the fuel tank.

• Periodically check and clean the filter.

• Do not unnecessarily disassemble sealed components.

Troubleshooting notesThe cause of malfunctions is not necessarily limited to the pump itself, but may also be related to the engine and/or fuel

systems. Further, the majority of malfunctions are the result of user error, and often can often be resolved through simple

checks and maintenance. Avoid any hasty removal of system components.

Basic Check Items

1 Late Injection Timing Fuel is injected when the piston is in the down stroke.

2 Cold EngineIgnition occurs late and combustion is prolonged.

3 Poor Fuel Combustibility

4 Rise and Fall of Oil Pressure Oil undergoes partial thermal breakdown.

1 Large Fuel Injection Quantity Air-fuel mixture becomes rich.

2 Low Intake Air Quantity Air quantity is insufficient due to air filter clogging.

3 Poor Fuel Atomization The ratio of fuel to air worsens.

4 Retarded Fuel Injection Timing Air-fuel mixing time is insufficient.

1 Engine Oil 7 Fuel Supply to the Pump

2 Coolant 8 Injector Injection Status

3 Fan Belt 9 Supply Pump Timing Mark

4 Air Cleaner 10Check for Loose or Disconnected Connectors, andModifications

5 Battery and Terminals 11 Idle Speed Status

6 Fuel System Leaks


2. DIAGNOSIS OVERVIEW

2.1 Diagnostic Work FlowDiagnostic Procedures

1 Receive malfunctioning vehicle

2 Question the user to verify the nature of themalfunction.

3 Does the malfunction reoccur? Refer to "Actions for Non-Reoccurring Malfunc-tions."

4 Verify the malfunction symptom at the actualvehicle.

5 Use the DST-2 to check for any DTCs. Proceed with diagnostics while referencing theDTC chart in the repair manual for the appropri-ate vehicle.

6 Use the DST-2 "Data Monitor" function to per-form checks while monitoring each input andoutput signal.

Proceed with diagnostics while referencing therepair manual for the appropriate vehicle.

7 Use the DST-2 active test function to operateeach output device with the ignition switch in theON position. Check for any abnormalities ineither the electrical circuits or the outputdevices.

Proceed with diagnostics while referencing therepair manual for the appropriate vehicle.

8 Was the malfunction cleared?

Return to step 3.


2.2 InquiriesUse the Common Rail System (CRS) troubleshooting questionnaire to consult with the customer and adequately grasp

the malfunction symptoms.

< NOTE >

Do not ask random questions. Rather, ask questions that will aid in narrowing down the possible malfunctioning system

while making educated guesses based on the actual symptoms.

Questioning pointsUse the following questions as a basis to fully grasp the malfunction.

• What?: Malfunction symptoms

• When?: Date, time, frequency of occurrence

• Where?: Road conditions

• Under what conditions?: Driving conditions, engine operating conditions, weather

• How?: Impression of how the symptoms occurred.

CRS troubleshooting questionnaireWhen the vehicle is received at the service center, it is necessary to verify the "malfunction symptoms" and the "gener-

ated malfunction data" with the customer. Consult with the customer using the CRS troubleshooting questionnaire. The

troubleshooting questionnaire is necessary for the following reasons.

Reasons• There are cases when the malfunction symptoms cannot be reproduced at the service center.

• The customer's complaint is not always limited to the malfunction.

• If the person performing repairs is not working from the correct malfunction symptoms, man-hours will be wasted.

• The questionnaire can aid the service center in diagnosing, repairing and verifying repair work.

Q002315E

Questioning Results

Inspection Results


(1) Questionnaire

Q002316E

CRS Troubleshooting Questionnaire

Vehicle Model

Previous Vehicles Driven:

Other Customer Information

Indications from the Customer

Questioning

Results

System Conditions Driving Conditions Road Surface Other Frequency of Occurrence

MIL Illumination No / Yes ( )

Main Area and Purpose of Use

Receiving Date

Date Registered

Occurrence Date

Service History No / Yes ( times)

Registration No.

Odometer Reading

Frame No.

Occurrence Speed ( ) km/hrShift Position ( ) RangeAt Start-UpDirectly after Start-UpUp to ( ) Minutes after Start Up to ( ) Minutes into Driving When ColdWhen WarmDuring OperationOther ( )

During Take-OffWhile CruisingWhen AcceleratingWhen DeceleratingWhen BrakingWhen TurningWhen StoppedNo RelationshipOther ( )

FlatUphillDownhillDry, Sealed roadWet, Sealed RoadUnsealed Road orRough Road SurfaceSnow-Covered or Icy RoadPotholes, Manholes, etc.Other ( )

AcceleratorOpening( ) % Outside AirTemperature ( ) C Weather( )

NormalOnly Once Occasionally

( ) Times per Day ( ) Times per Week ( ) Times per Month

ReoccurrenceConditions

Occurs Regularly Occurs OccasionallyContinues to AppearAfter One Occurrence

Does Not Reoccur

Malfunction Details: Time of occurrence, place and driving conditions during reoccurrence.

Fuel Pressure when Engine is Stopped

1 Minute after Turning Engine OFF

DTC Normal

Abnormal DTC (All Codes)Illuminated No Yes

DTC Check

Inspection

Results

Additional Items

o


2.3 Non-Reoccurring MalfunctionsIn cases where the malfunction does not reoccur, perform the actions below to determine the cause of the malfunction.

Action

Malfunction Symptom

Fully Dis-

charged Bat-

tery

Engine will not

Start

Idle Speed,

Engine Stall,

Sputtering,

Poor Acceler-

ation

Verify that there is no DTC stored in the memory. No Yes Yes

Use the questionnaire as a basis to perform a reoccurrence test in"Reoccurrence" mode. Use this data (engine ECU voltage value, etc.)to determine the cause of the malfunction.

Yes Yes Yes

Assume that an electrical sys-tem wiring harness or connectoris the cause of the malfunction.Shake the wiring by hand tocheck whether a malfunctionoccurs and a DTC is generated.

No Yes Yes

Assume that an electrical system female connector terminal is thecause of the malfunction and verify that the connection points are notdefective.

No Yes Yes

Use a dryer to heat the acceler-ator pedal position sensor andother electronic components.Check for changes in the volt-age value (resistance value).

< CAUTION >

• Do not exceed 60°C (still touchable by hand) when heating.

• Do not remove the component cases and add heat directly to

electronic parts.

No No Yes

Verify whether malfunction symptoms occur under heavy engineloads (headlights, A/C, wiper, etc. switches ON.)

No No Yes

If any commercial electrical products have been installed, removesuch products and verify whether the malfunction symptoms occur.

Yes Yes Yes

Q002317

Recommended Tool: KOWA Precision HandlingFeeler Gauge Set (KLM-10-20)Depending on the terminal, a matchingsize may not be available

Insert the male terminal thatmatches the shape of thefemale terminal and checkfor looseness. Q002318

Q002319


If it is likely that the malfunctionoccurs in rainy or high-tempera-ture weather, spray the vehiclewith water and verify whetherthe malfunction occurs.

< CAUTION >

• Do not spray water directly into the engine compartment.

Spray water in mist form on all surfaces of the radiator to indi-

rectly change temperature and humidity.

• Do not spray water directly on electrical parts.

No Yes Yes

Action

Malfunction Symptom

Fully Dis-

charged Bat-

tery

Engine will not

Start

Idle Speed,

Engine Stall,

Sputtering,

Poor Acceler-

ation

Mist State

Q002320E


3. DTC READING (FOR TOYOTA VEHICLES)

3.1 DST-2The DST-2 can check for DTCs in either normal or check mode. In comparison to the normal mode, the check mode

has higher sensitivity in detecting malfunctions. Check mode is used when detection is not possible in normal mode,

regardless of the assumed abnormality.

3.2 DTC Check (Code Reading via the DST-2)Connect the DST-2 to the DLC3 connector.

Operate the DST-2 in accordance with the instructions shown on the display to view the "DTC check" screen. Select

either the normal or check mode to verify the DTC.

3.3 DTC Memory Erasure (via the DST-2)To erase DTC codes, follow the instructions on the display to view the "DTC and Freeze Data Erasure" screen.

< CAUTION >

• If the DTC cannot be erased, cycle the ignition switch OFF and back ON, and then perform code erasure again.

• Do not use the DST-2 to erase the DTC until the cause of the malfunction is clear.

Q000916E



DTC (ECD Erasure)

NG : - OK : +


4. TROUBLESHOOTING BY SYSTEM

4.1 Intake System DiagnosisClogged air cleaner element

4.2 Fuel System DiagnosisClogged air cleaner element

1 Clogged air cleaner element Clean or replace the air cleaner.

2 Check the suction path for leaks.• Suction path joints• Suction pipes, hoses

Repair or replace the malfunctioning compo-nent.

Normal

1 Fuel system check (remaining fuel quantity, fuelproperties)• Check the amount of fuel remaining in the

tank.• Check the condition of the fuel. Request

engine analysis from a third party as neces-sary.- Color (no color, brownish, milky)- Odor (kerosene, heavy oil, irritating odor)- Separation of materials (water, foreign

objects)- Viscosity (high/low viscosity, wax consis-

tency)

Add fuel or replace components (clean tank.)

NG

OK

NG

OK

NG

OK


2 Fuel tank interior check (modification/additions,position of fuel pipe inlet/outlet, clogging andholes)• Check the tank for modifications or additions.

Consult with the user.- Fuel inlet/outlet position, tank piping- Foreign material inside the tank, water sep-

aration- Tank-internal Zn cladding- Check the tank-internal fuel piping for the

following.- Inlet/outlet position (below position "E")- Inlet clogging, bent or deformed piping

(crushed pipe)- Crushed piping connections

Restore the fuel tank.

3 Tank-external fuel path conditions (crushedhose, clogging, air introduction at hose connec-tion)• Check the condition of the hose.

- Crushing around bands, over-bending- Pinched or crushed by other parts

• Air introduction through fuel system connec-tion points- Looseness- Hose deterioration (Verify by hand or visu-

ally that there is no rubber hardening/split-ting.)

< CAUTION >

Be cautious when vacuum pressure is

present, as air will be drawn into the

hose.

Repair or replace the hose.

4 Primary filter, sedimentor check• Check for primary filter clogging and dirt.• Check sedimentor water volume.

Replace the filter, and drain water from the sedi-mentor.

5 Looseness at priming attachment point check• Check the following.

- Looseness at the priming attachment point- Does the piston stick out?- Fuel leakage (oozing)

Tighten or replace the priming pump.

NG

OK

NG

OK

NG

OK

NG

OK


(1) Fuel pressure test procedure

• Connect the DST-2 to the vehicle-side test connector.

- With the vehicle idling, verify the rail pressure displayed on the DST-2.

System selection screen: Rail a ECU Data Monitor

6 Filter (supply pump inlet) clogging• Fuel filter

- Check for fuel delivery from the primingpump.

• Gauze filter- Visually check for clogging due to foreign

material.

Clean the gauze filter, fuel filter and fuel pipingsystem, or replace the filters.

7 Oil level increase (engine internal leak)• Verify whether the oil level increases on the

oil level gauge.

Check the engine.

8 High-pressure piping and CRS component(injector supply pump, rail) fuel leaks (engineexternal leak) (Refer to "(2) Fuel leak check".)• Connect the DST-2 to the diagnostic connec-

tor. Activate the "Fuel Leak Check Function"within the active test.

• Visually check and specify areas that leakfuel.

< CAUTION >

In the event of a large fuel leak down-

stream of the flow damper, be aware

that fuel flow will stop and the leak will

cease due to flow damper operation.

Repair leaking high-pressure piping or replaceleaking parts.

Normal

Item Name (Abbrevi-

ated)

Explanation Check Conditions Reference Value Items of Importance

During an Abnormal-

ity

Rail Pressure (RP) • Displays the fuelpressure in the rail.

• Display range: 0MPa to 255 MPa

Following enginewarm-up, when theengine is rotating

Fuel pressure in therail is displayed withina range of 30 MPa to160 MPa.

PCR1, PCR2 signals(rail assembly)

NG

OK

NG

OK

NG

OK


(2) Fuel leak check

• Connect the DST-2 to the vehicle-side test connector.

• With the vehicle idling, perform the active test by following the instructions on the DST-2 display.

System selection screen: TCCS a Active Test

• Verify that there are no fuel system leaks during the active test (when fuel pressure is being applied to the rail.)

4.3 Basics of Electrical/Electronic Circuit Checks

(1) ECU terminal voltage and waveform measurements

• When measuring the voltage and resistance of each terminal, insert the multimeter probe into the rear side of the

wiring harness connector. If connectors are too small for the probe to be inserted easily, insert a fine metal wire into

the rear of the connector and touch the wire to the probe.

< NOTE >

The number of each terminal can be seen from the rear side of the wiring harness.

Item Name Description Control Conditions

High-Pressure Fuel System Check Raise engine speed to 2000 rpm, andthen use the active test to place thefuel inside the rail under high pres-sure.

< CAUTION >

Engine speed cannot be

raised by stepping on the

accelerator pedal.

• Following engine warm-up, whenthe engine is at idle speed

• The vehicle speed sensor is operat-ing normally, and speed is 0 km/h.

Q002326E

Ground

Ground

Ground

Engine ECU Side

Wiring HarnessSide


(2) Open circuit check

• When dealing with a wiring harness open circuit like that depicted in diagram 1, check continuity and/or voltage to

determine the location of the open circuit.

Continuity Check1) Remove connectors "A" and "C", and then measure resis-

tance between the two.

< NOTE >

Measure resistance while gently shaking the wiring har-

ness up and down, and side-to-side.

2) As shown in diagram 2, there is no continuity (open circuit)

between terminal 1 of connector "A" and terminal 1 of con-

nector "C". However, there is continuity between terminal 2

of connector "A" and terminal 2 of connector "C". Therefore,

there is an open circuit between terminal 1 of connector "A"

and terminal 1 of connector "C".

3) Remove connector "B" and measure the connector resis-

tance.

4) As shown in diagram 3, there is continuity between terminal

1 of connector "A" and terminal 1 of connector "B1". Howev-

er, there is no continuity (open circuit) between terminal 1 of

connector "B2" and terminal 1 of connector "C". Therefore,

there is an open circuit between terminal 1 of connector "B2"

and terminal 1 of connector "C".

Q002327E

Diagram 1 Engine ECU

SensorOpen

Circuit1 1 1 1

2 2 2 2

ABC

Q002328E

Diagram 2

Sensor

EngineECU

1

2 2

1

2

ABC

Standard Value 1Ω or less

Q002329E

Diagram 3

Sensor

EngineECU

1

2

1

2

1

2

1

2

AC B2 B1


Voltage Check1) For the circuit that applies voltage to the ECU connector ter-

minals, check for an open circuit by performing a voltage

check.

2) As shown in diagram 4, with all connectors connected, mea-

sure the voltage for the ECU 5 V output terminal between

the body ground and terminal 1 of connector "A". Next mea-

sure voltage for terminal 1 of connector "B" and terminal 1 of

connector "C" in the same fashion.

3) The faulty circuit and measurement results are shown be-

low.

(3) Short circuit check

• As shown in diagram 5, if there is a short in the wiring harness ground, perform a "Ground Continuity Check" to de-

termine the cause of the short.

Q002330E

Diagram 4

Sensor

1

2 2

11

2ABC

0 V5 V

5 V

Measurement Results

• Voltage between terminal 1 of con-nector "A" and the body ground is 5V.

• Voltage between terminal 1 of con-nector "B" and the body ground is 5V.

• Voltage between terminal 1 of con-nector "C" and the body ground is 0V.

Faulty ItemThere is an open circuit in the wiringharness between terminal 1 of connec-tor "B" and terminal 1 of connector "C".

Q002331E

Diagram 5

Sensor

Engine ECU

ShortCircuit


Ground Continuity Check1) Remove connector "A" and connector "C", and then mea-

sure the resistance respectively between terminals 1 and 2

of connector "A" and ground.

< NOTE >

Measure resistance while gently shaking the wiring har-

ness up and down, and side-to-side.

2) As shown in diagram 6, there is continuity between terminal

1 of connector "A" and the body ground (short circuit). How-

ever, there is no continuity between terminal 2 of connector

"A" and the body ground. Therefore, there is a short circuit

between terminal 1 of connector "A" and terminal 1 of con-

nector "C".

3) Remove connector "B" and measure the resistance be-

tween terminal 1 of connector "A" and the body ground, and

between terminal 1 of connector "B2" and the body ground.

4) The faulty circuit and measurement results are shown be-

low.

Q002332E

Diagram 6

Sensor

EngineECU

1

2 2

11

2

ABC

Standard Value 1Ω or less

Q002333E

Diagram 7

Sensor

EngineECU

1

2

1

2

1

2

1

2

AC B2 B1

MeasurementResults

• There is no continuity between termi-nal 1 of connector "A" and the bodyground.

• There is continuity between terminal1 of connector "B2" and the bodyground.

Faulty Item There is a short circuit between terminal1 of connector "B2" and terminal 1 ofconnector "C".


(4) Connector connection fault verification method

• Simultaneously perform the data monitor and connector voltage measurements.

Q002334E

1. Read the "Coolant Temperature Output Voltage" value using the DST-2 data monitor.

2. Measure the voltage directly from the corresponding ECU terminal.

Ex.) Coolant temperature sensor

If "1" is unsatisfactory and "2" is satisfactory, the connector connection is judged as faulty.

Since some malfunctions only occur intermittently, measure voltage while pulling and shaking the

wires in order to try to get the malfunction to reoccur.

Voltage Measurement

No.2 - 34P No.5 - 31P35 41 137 143

62 69 162 167


5. TROUBLESHOOTING

5.1 Troubleshooting According to Malfunction Symptom (for TOYOTA Ve-hicles)

(1) Malfunction Indicator Lamp (MIL) is lit.

Clogged air cleaner element

(2) The engine is hard to start.


Description

The check engine warning light is lit when the engine is running, or before the engine is started.

Possible Cause

The DTC is recorded in the engine ECU.

1 Connect the DST-2 and read the DTC. Inspect the check engine warning light circuit.

Troubleshoot the corresponding DTC.

Description

The starter turns at normal speed, but the engine takes too long to start.

Possible Cause

• Start signal circuit• Glow control system• Crankshaft position sensor• Engine ECU power supply circuit• Injector• Supply pump• Cylinder recognition sensor

1 Use the DST-2 to verify whether the coolanttemperature is at the glow system operatingtemperature. In addition, verify whether batteryvoltage is being supplied to the glow plugs atthe designated times.

Repair the glow control system. (Refer to theglow control system check procedure issued bythe vehicle manufacturer.)

2 Use the DST-2 to monitor engine speed whilecranking the engine. Verify whether enginespeed is being correctly output.

Check the crankshaft position sensor. (Refer tothe crankshaft position sensor check procedureissued by the vehicle manufacturer.)

NG

OK

NG

OK

NG


3 Verify the output waveform of the cylinder rec-ognition sensor. (Refer to the cylinder recogni-tion sensor check procedure issued by thevehicle manufacturer.)

Repair or replace the cylinder recognition sen-sor and/or the corresponding circuit.

4 Check each injector. (Refer to the injector checkprocedure issued by the vehicle manufacturer.)

Repair or replace the injector and/or the corre-sponding circuit.

5 Verify whether there is a start signal whencranking the engine by checking the engineECU start signal terminal.

Repair the start signal circuit.

6 Check the engine ECU power supply. (Refer tothe engine ECU power supply circuit diagramissued by the vehicle manufacturer.)

Repair the engine ECU power supply.

7 Check the supply pump and the supply pumpdrive circuit. (Refer to the supply pump drive cir-cuit diagram issued by the vehicle manufac-turer.)

Repair or replace the supply pump and drive cir-cuit.

Troubleshooting complete

OK

NG

OK

NG

OK

NG

OK

NG

OK

NG

OK


(3) The engine stalls when idling.


Description

The engine stalls after starting or when idling.

Possible Cause

• Crankshaft position sensor• Engine ECU power supply circuit• Injector• Supply pump• Engine cooling system• Start signal circuit

1 Verify that the engine is not overheated. Repair the engine cooling system.

2 Check the crankshaft position sensor outputwaveform. (Refer to the crankshaft position sen-sor check procedure issued by the vehicle man-ufacturer.)

Repair or replace the crankshaft position sensorand/or the corresponding circuit.










NG

OK

NG

OK

NG

OK

NG

OK

NG

OK

NG

OK


(4) The engine cranks normally, but does not start.


Description

The engine is cranked at the normal speed, but does not start.

Possible Cause

• Crankshaft position sensor• Engine ECU power supply circuit• Injector• Supply pump• Start signal circuit

1 Use the DST-2 to verify whether the coolanttemperature is at the glow system operatingtemperature. In addition, verify whether batteryvoltage is being supplied to the glow plugs atthe designated times.

Repair the glow control system. (Refer to theglow control system check procedure issued bythe vehicle manufacturer.)

2 Monitor engine speed while cranking theengine. Verify whether engine speed is beingcorrectly output.

Check the crankshaft position sensor. (Refer tothe crankshaft position sensor check procedureissued by the vehicle manufacturer.)










NG

OK

NG

OK

NG

OK

NG

OK

NG

OK

NG

OK


(5) Idle instability following engine start


Description

Idle speed after starting the engine is abnormal.

Possible Cause

• Injector• Supply pump• Fuel filter• Engine ECU• Rail pressure sensor



2 Check the fuel filter. Replace the fuel filter.



4 Check the rail pressure sensor and the corre-sponding circuit. (Refer to the rail pressure sen-sor check procedure issued by the vehiclemanufacturer.)

Repair or replace the rail pressure sensor andthe corresponding circuit.


NG

OK

NG

OK

NG

OK

NG

OK


(6) The engine returns to idle speed too slowly, or does not return at all.


Description

The time required for the engine to return to idle speed is longer than normal, or the engine does not return to idlespeed.

Possible Cause

• Accelerator position sensor• Injector• Supply pump

1 Perform the accelerator pedal position sensorfunction check. (Refer to the accelerator posi-tion pedal sensor check procedure issued bythe vehicle manufacturer.)

Repair or replace the accelerator position sen-sor and/or the corresponding circuit.






NG

OK

NG

OK

NG

OK


(7) Rough idle


Description

Idle speed fluctuates, causing the engine to vibrate.

Possible Cause

• Engine cooling system• Crankshaft position sensor• Engine• Supply pump• Injector

1 Check parts that may be a source of abnormalengine vibration.

Repair the engine.




4 Check the crankshaft position sensor. (Refer tothe crankshaft position sensor check procedureissued by the vehicle manufacturer.)





NG

OK

NG

OK

NG

OK

NG

OK

NG

OK


(8) The engine stalls when decelerating.


Description

The engine suddenly stops when decelerating.

Possible Cause

• Engine cooling system• Crankshaft position sensor• Engine ECU power supply circuit• Supply pump• Injector• Start signal circuit













NG

OK

NG

OK

NG

OK

NG

OK

NG

OK

NG

OK


(9) Poor engine output, poor acceleration


Description

Deficient engine performance.

Possible Cause

• EGR system• Injector• Mass Air Flow (MAF) meter• Crankshaft position sensor• Accelerator position sensor• Boost pressure sensor• Supply pump• Start signal circuit• Air cleaner, duct

1 Check for air cleaner clogging and/or damage. Replace the air cleaner or repair the air duct.








6 Check the MAF meter and the correspondingcircuit. (Refer to the MAF meter check proce-dure issued by the vehicle manufacturer.)

Repair or replace the MAF meter and/or the cor-responding circuit.

NG

OK

NG

OK

NG

OK

NG

OK

NG

OK

NG

OK


7 Check the Exhaust Gas Recirculation (EGR)system. (Refer to the EGR system check proce-dure issued by the vehicle manufacturer.)

Repair or replace the EGR system.

8 Perform the accelerator pedal position sensorfunction check. (Refer to the accelerator posi-tion pedal sensor check procedure issued bythe vehicle manufacturer.)

Repair or replace the accelerator position sen-sor and/or the corresponding circuit.

9 Check the boost pressure sensor and the corre-sponding circuit. (Refer to the boost pressuresensor check procedure issued by the vehiclemanufacturer.)

Repair or replace the boost pressure sensorand/or the corresponding circuit.




NG

OK

NG

OK

NG

OK

NG

OK


(10) Knocking, abnormal noise


Description

Abnormal combustion occurs, and a knocking sound is generated.

Possible Cause

• Engine• Injector• Glow control system• Crankshaft position sensor

1 Repair the glow control system. (Refer to theglow control system check procedure issued bythe vehicle manufacturer.)

Repair the glow control system.





4 Check engine parts that may be a source ofabnormal combustion.

Repair the engine.


NG

OK

NG

OK

NG

OK

NG

OK


(11) Poor fuel economy


Description

More fuel than normal is being consumed.

Possible Cause

• Engine• Injector• Supply pump





3 Check parts that may be a source of poor fueleconomy.

Repair the engine.


NG

OK

NG

OK

NG

OK

R e p a i r S e c t i o n

2–119

(12) Black Smoke


Description

Black smoke is being exhausted.

Possible Cause

• Injector• Supply pump• EGR system• Engine ECU• Electronic control throttle• Rail pressure sensor• Mass Air Flow (MAF) meter• Boost pressure sensor

1 Check for air cleaner clogging and/or damage. Replace the air cleaner or repair the air duct.

2 Check the electronic control throttle and the cor-responding circuit. (Refer to the electronic con-trol throttle check procedure issued by thevehicle manufacturer.)

Repair or replace the electronic control throttleand/or the corresponding circuit.

3 Check the MAF meter and the correspondingcircuit. (Refer to the MAF meter check proce-dure issued by the vehicle manufacturer.)

Repair or replace the MAF meter and/or the cor-responding circuit.



5 Check the boost pressure sensor and the corre-sponding circuit. (Refer to the boost pressuresensor check procedure issued by the vehiclemanufacturer.)

Repair or replace the boost pressure sensorand/or the corresponding circuit.



NG

OK

NG

OK

NG

OK

NG

OK

NG

OK

NG









OK

NG

OK

NG

OK

NG

OK


(13) White smoke


Description

White smoke is being exhausted.

Possible Cause

• Fuel filter• Injector• Supply pump• EGR system• Engine ECU• Electronic control throttle• Rail pressure sensor

1 Check the fuel filter. Replace the fuel filter.









6 Check the electronic control throttle and the cor-responding circuit. (Refer to the electronic con-trol throttle check procedure issued by thevehicle manufacturer.)

Repair or replace the electronic control throttleand/or the corresponding circuit.


NG

OK

NG

OK

NG

OK

NG

OK

NG

OK

NG

OK


5.2 Other Malfunction SymptomsMalfunctions caused by components other than the CRS

There are occasions when a malfunction that appears to be generated by the CRS is actually caused by a different com-

ponent or system. For instance, engine mechanical parts and the fuel system may cause malfunction symptoms iden-

tical to symptoms generated by the CRS. When troubleshooting, do not simply assume that the source of a malfunction

is the CRS. Consider all causes should be exhaustively considered while verifying the list below.

Malfunction

Symptom

Faulty Item Cause Action

Insufficient Power

Intake system Clogged air cleaner element Clean or replace the air cleaner element.

Fuel system

Air mixed with the fuel system Perform fuel system air bleeding.

Faulty fuel filter Replace the filter.

Insufficient fuel Add fuel and perform fuel system airbleeding.

Improper fuel Switch to the correct fuel.

EngineCompression pressure abnormality Refer to the engine repair manual.

Piston, cylinder liner and/or piston ring

Other Overheat

Faulty starting

Intake system Clogged air cleaner element Clean or replace the air cleaner element.

Fuel system

Insufficient fuel Add fuel and perform fuel system airbleeding.

Improper fuel Replace the filter.

Fuel system clog Clean the fuel system.

Air introduction through fuel system con-nection points

Tighten all connections.

Fuel filter clog Replace the fuel filter.

Loose injection piping connections Tighten connecting nuts.

Electrical sys-tem

Faulty battery Check the battery.

Faulty starter wiring Replace the starter wiring.

Loose battery cables Tighten the battery terminal connections,or replace the cables.

Faulty starting

Electrical sys-tem

Faulty starter operation Replace the starter assembly.

Faulty glow plug system Replace the glow plugs.

Lubricationsystem

Excessive engine oil viscosity Replace with oil of appropriate viscosity.

Engine

Burnt pistons Replace the piston, piston ring and cylin-der liner.

Burnt bearings Replace the bearing and crankshaft.

Low compression pressure Overhaul the engine.

OtherRing gear damage Replace the ring gear and/or starter pin-

ion gear.


Faulty idling Engine

Poor valve clearance Adjust the valve clearance or replace thebearing.

Poor valve seat contact Break in, or replace the valve and valveseat.

Low coolant temperature Perform warm-up operation.

Large difference in cylinder-to-cylindercompression pressure

Overhaul the engine.

Malfunction

Symptom

Faulty Item Cause Action


6. DIAGNOSIS CODES (DTC)

6.1 DTC Chart (Example)DTC Structure

P####: Powertrain-related (engine, drive system)

U####: Network-related (vehicle communication)

DTC AssignmentPO###: Determined by SAE/ISO

P1###: Determined by manufacturer

P2###: Determined by manufacturer

P3###: Mixture of items determined by SAE/ISO and items determined by the vehicle manufacturer.

DTC Chart (example for HINO and TOYOTA vehicles)DTC codes that apply to the CRS are listed below (compatible with the DST-2.)

DTC DTC Description

P0006 Fuel shutoff valve "A" control circuit low voltage

P0007 Fuel shutoff valve "A" control circuit high voltage

P0016 Crankshaft position sensor, cylinder recognition sensor correlation

P0030 A/F sensor heater control circuit

P0031 A/F sensor heater control circuit low voltage

P0032 A/F sensor heater control circuit high voltage

P0036 A/F sensor heater control circuit

P0037 A/F sensor heater control circuit low voltage

P0045 Turbo/supercharger control solenoid open circuit

P0049 Turbo/supercharger overspeed

P0087 Fuel/rail pressure too low

P0088 Fuel/rail pressure too high

P0093 Fuel system leak maximum quantity detection

P0095 Intake air temperature sensor 2, circuit related

P0097 Intake air temperature sensor 2 circuit low voltage

P0098 Intake air temperature sensor 2 circuit high voltage

P0100 Mass Air Flow (MAF) meter, circuit related

P0101 MAF meter circuit range/performance

P0102 MAF meter circuit low input

P0103 MAF meter circuit high input

P0105 Boost pressure sensor, circuit related

P0107 Boost pressure sensor circuit low input

P0108 Boost pressure sensor circuit high input

P0112 Boost pressure sensor 1 circuit low voltage

P0113 Boost pressure sensor 1 circuit high voltage

P0115 Coolant temperature sensor, circuit related

P0117 Coolant temperature sensor circuit low voltage


P0118 Coolant temperature sensor circuit high voltage

P0119 Coolant temperature sensor circuit intermittent operation

P0120 Accelerator position sensor, switch "A" circuit related

P0121 Accelerator position sensor switch "A" circuit range/performance

P0122 Accelerator position sensor switch "A" circuit low voltage

P0123 Accelerator position sensor switch "A" circuit high voltage

P0124 Accelerator position sensor switch "A" circuit intermittent operation

P0168 Fuel temperature too high

P0180 Fuel temperature sensor, "A" circuit related

P0181 Fuel temperature sensor "A" circuit range/performance

P0182 Fuel temperature sensor "A" circuit low voltage

P0183 Fuel temperature sensor "A" circuit high voltage

P0184 Fuel temperature sensor "A" circuit intermittent operation

P0185 Fuel temperature sensor, "B" circuit related

P0186 Fuel temperature sensor "B" circuit range/performance

P0187 Fuel temperature sensor "B" circuit low voltage

P0188 Fuel temperature sensor "B" circuit high voltage

P0189 Fuel temperature sensor, "B" circuit intermittent operation

P0190 Rail pressure sensor, circuit related

P0191 Rail pressure sensor circuit range/performance

P0192 Rail pressure sensor circuit low voltage

P0193 Rail pressure sensor circuit high voltage

P0194 Rail pressure sensor circuit intermittent operation

P0200 Injector open circuit

P0201 Injector open circuit- #1 cylinder







P0217 Engine overheat

P0218 Transmission overheat

P0219 Engine overrun

P0230 Fuel pump, primary circuit related

P0234 Turbo/supercharger overboost

P0237 Boost pressure sensor circuit low voltage

P0263 Cylinder correction quantity error- #1 cylinder




DTC DTC Description




P0299 Turbo/supercharger supercharge deficiency

P0335 Crankshaft position sensor, "A" circuit related

P0339 Crankshaft position sensor "A" circuit intermittent operation

P0340 Cylinder recognition sensor, "A" circuit related

P0400 EGR flow volume abnormality

P0404 EGR control circuit range/performance

P0405 EGR sensor "A" circuit low voltage

P0406 EGR sensor "A" circuit high voltage

P0407 EGR sensor "B" circuit low voltage

P0408 EGR sensor "B" circuit high voltage

P0500 Vehicle speed sensor, "A" circuit related

P0501 Vehicle speed sensor "A" circuit range/performance

P0504 Brake switch "A", "B" correlation

P0510 Throttle position switch closed

P0524 Engine oil pressure too low

P0540 Intake air heater "A" circuit

P0544 Exhaust gas temperature sensor, circuit related

P0545 Exhaust gas temperature sensor circuit low voltage

P0546 Exhaust gas temperature sensor circuit high voltage

P0560 Battery voltage

P0605 Engine ECU internal malfunction

P0607 Engine ECU internal malfunction

P0611 EDU malfunction

P0617 Starter relay circuit high voltage

P0627 Fuel pump "A" open control circuit

P0686 Engine ECU power supply relay control circuit low voltage

P0704 Clutch switch input circuit abnormality

P0710 Transmission oil temperature sensor, "A" circuit related

P0715 Turbine speed sensor, "A" circuit related

P0753 Shift solenoid "A" actuation related

P0758 Shift solenoid "B" actuation related

P0850 Parking/neutral switch, input circuit related

P2002 Particulate Matter (PM) capture efficiency at or below specified value

P2031 Exhaust gas temperature sensor, circuit related

P2032 Exhaust gas temperature sensor circuit low voltage

P2033 Exhaust gas temperature sensor circuit high voltage

P2047 Exhaust gas fuel addition valve abnormality

P2120 Accelerator position sensor, switch "D" circuit related

P2121 Accelerator position sensor switch "D" circuit range/performance

DTC DTC Description


P2122 Accelerator position sensor, switch "D" circuit low input

P2123 Accelerator position sensor, switch "D" circuit high input

P2125 Accelerator position sensor, switch "E" circuit related

P2127 Accelerator position sensor, switch "E" circuit low input

P2128 Accelerator position sensor, switch "E" circuit high input

P2138 Accelerator position sensor, switch "D"/"E" circuit voltage correlation

P2226 Atmospheric pressure sensor, circuit related

P2228 Atmospheric pressure sensor circuit low voltage

P2229 Atmospheric pressure sensor circuit high voltage

DTC DTC Description

DENSO CORPORATION Service Department

Edited and published by:

1-1 Showa-cho, Kariya, Aichi Prefecture, Japan

Published : August 2004Second Issu: September 2007